CC Flashcards

Question 1

Q

10 6th

Kilo
Mega
Milli
Micro

Question 2

Q

The prefix which means 10 -9 is:

Micro
Milli
Nano
Pico

Question 3

Q

Concentration expressed as the amount of solute per 100 parts of solution:

Molarity
Normality
Percent solution
Ratio

Answer

A

Percent solution

Question 4

Q

Indication of relative concentration:

Dilution
Molarity
Normality
Ratio

Question 5

Q

What is the molarity of a solution that contains 18.7 grams of KCl in 500 mL (MW 74.5)?

0.1
0.5
1.0
5.0

Answer

A

0.5

M = 18.7 g / (74.5)(0.5L) = 0.5 M

Question 6

Q

How much 95% v/v alcohol is required to prepare 5L of 70% v/v alcohol?

2.4 L
3.5 L
3.7 L
4.4 L

Answer

A

3.7 L

C1V1 = C2V2
V1 = (70)(5L) / 95 = 3.7 L

Question 7

Q

A colorimetric method calls for the use of 0.1 mL serum, 5 mL of the reagent and 4.9 mL of water. What is the dilution of the serum in the final solution?

1 to 5
1 to 10
1 to 50
1 to 100

Answer

A

1 to 100

Amount of serum: 0.1 mL
Total volume: 10 mL
Dilution: 0.1:10 or 1:100

Question 8

Q

Convert 72 Fahrenheit to its Celsius equivalent:

12.2C
22.2C
40.2C
44.4C

Answer

A

22.2C

C = 5/9 (F - 32)
= 5/9 (72 - 32)
= 22.2C

Question 9

Q

Convert 100 Celsius to its Kelvin equivalent:

73.15K
173.15K
273.15K
373.15K

Answer

A

373.15K

K = C + 273.15
= 100 + 273.15
= 373.15K

Question 10

Q

Most basic pipette:

Automatic pipette
Glass pipette

Answer

A

Glass pipette

ROUTINELY USED: automatic pipette
MOST BASIC: glass pipette

Question 11

Q

Does not have graduations to the tip:

Mohr pipet
Serologic pipet
Micropipet
None of these

Answer

A

Mohr pipet

A Mohr pipet does not have graduations to the tip.
It is a self-draining pipet, but the tip should not be allowed to touch the vessel while the pipet is draining.

Question 12

Q

Pipets are used with biologic fluids having a viscosity greater than that of water:

Mohr pipets
Ostwald-Folin pipets
Pasteur pipets
Volumeteric pipets

Answer

A

Ostwald-Folin pipets

Ostwald-Folin pipets are used with biologic fluids having a viscosity greater than that of water. They are blowout pipets, indicated by two etched continuous rings at the top.

Question 13

Q

Pipette with BULB CLOSER TO THE DELIVERY TIP and are used for accurate measurement of VISCOUS FLUIDS, such as blood or serum:

Pipette with cylindrical glass bulb near the CENTER of the pipette that helps to distinguish them from other types of transfer pipettes.

Ostwald-Folin pipette
Volumetric pipette

Answer

A

Ostwald-Folin pipette
Volumetric pipette

Question 14

Q

Extremely inert, excellent temperature tolerance and chemical resistance; used for stir bars, stopcocks and tubing:

Polyethylene
Polycarbonate
Polystyrene
Teflon

Answer

A

Teflon

POLYETHYLENE
 Widely used in plastic ware, too, including test tubes, bottles, graduated tubes, stoppers, disposable transfer pipets, volumetric pipets, and test tube racks.
 May bind or absorb proteins, dyes, stains, and picric acid

POLYCARBONATE
 Used in tubes for centrifugation, graduated cylinders, and flasks
 Usable temperature range is broad: –100° C to +160° C
 Very strong plastic but is not suitable for use with strong acids, bases, and oxidizing agents
 May be autoclaved but with limitations

POLYSTYRENE
 Rigid, clear type of plastic that should not be autoclaved
 Used in an assortment of tubes, including capped graduated tubes and test tubes
 Not resistant to most hydrocarbons, ketones, and alcohols

TEFLON
 Widely used for manufacturing stirring bars, tubing, cryogenic vials, and bottle cap liners
 Almost chemically inert and is suitable for use at temperatures ranging from –270° C to +255° C
 Resistant to a wide range of chemical classes, including acids, bases, alcohol, and hydrocarbons

Question 15

Q

Horizontal-head centrifuge:

Cytocentrifuge
Fixed-angle head centrifuge
Swinging bucket centrifuge

Answer

A

Swinging bucket centrifuge

HORIZONTAL-HEAD OR SWINGING BUCKET CENTRIFUGE
* HORIZONTAL WHEN MOVING OR SPINNING
* VERITICAL WHEN NOT MOVING
Cups holding the tubes of material to be centrifuged occupy a vertical position when the centrifuge is at rest but assume a horizontal position when the centrifuge revolves

Question 16

Q

It is used when rapid centrifugation of solutions containing small particles is needed; an example is the microhematocrit centrifuge:

Horizontal-head centrifuge
Fixed-angle head centrifuge
Ultracentrifuge
Cytocentrifuge

Answer

A

Fixed-angle head centrifuge

Question 17

Q

High-speed centrifuges used to separate layers of different specific gravities, commonly used to separate lipoproteins:

Horizontal-head centrifuge
Fixed-angle head centrifuge
Ultracentrifuge
Cytocentrifuge

Answer

A

ULTRACENTRIFUGE

High-speed centrifuges used to separate layers of different specific gravities
Commonly used to separate lipoproteins
Usually refrigerated to counter heat produced through friction

Question 18

Q

Uses a very high-torque and low-inertia motor to spread MONOLAYER OF CELLS rapidly across a special slide for critical morphologic studies:

Horizontal-head centrifuge
Fixed-angle head centrifuge
Ultracentrifuge
Cytocentrifuge

Answer

A

CYTOCENTRIFUGE

Uses a very high-torque and low-inertia motor to spread monolayers of cells rapidly across a special slide for critical morphologic studies
Used for blood, urine, body fluid, or any other liquid specimen that can be spread on a slide

Question 19

Q

The speed of the centrifuge should be checked every 3 months with:

Tachometer
Wiper
Potentiometer
Ergometer

Answer

A

Tachometer

Question 20

Q

Calibration of centrifuges is customarily performed every ______.

Daily
Weekly
Every 3 months (quarterly)
Yearly

Answer

A

Every 3 months (quarterly)

Photoelectric tachometer or strobe tachometer

CAP recommends that the number of revolutions per minute for a centrifuge used in chemistry laboratories be checked every 3 months

Question 21

Q

Centrifuges are routinely disinfected on a ___ basis.

Daily
Weekly
Monthly
Quarterly

Answer

A

Weekly

Calibration of centrifuges is customarily performed every 3 months, and the appropriate relative centrifugal force for each setting is recorded.

Centrifuges are routinely disinfected on a weekly basis.

Question 22

Q

HIGHLY PURIFIED SUBSTANCES of a known composition:

Control
Standard

Answer

A

Standard

A standard may differ from a control in its overall composition and in the way it is handled in the test.

Standards are the best way to measure ACCURACY. Standards are used to establish reference points in the construction of graphs (e.g., manual hemoglobin curve) or to calculate a test result.

Question 23

Q

It represents a specimen that is SIMILAR IN COMPOSITION TO THE PATIENT’S WHOLE BLOOD or plasma:

Control
Standard

Answer

A

Control

The value of a control specimen is known. Control specimens are tested in exactly the same way as the patient specimen and are tested daily or in conjunction with the unknown (patient) specimen.

Controls are the best measurements of PRECISION and may represent normal or abnormal test values.

Question 24

Q

Water produced using either an anion or a cation EXCHANGE RESIN, followed by replacement of the removed ions with hydroxyl or hydrogen ions.

Deionized water
Distilled water
RO water

Answer

A

Deionized water

Question 25

Q

The PUREST TYPE OF REAGENT WATER is:

Type I
Type II
Type III
All are equal

Question 26

Q

Chemicals that are used to manufacture drugs:

Technical or commercial grade
Analytical grade
Ultrapure grade
USP and NF chemical grade

Answer

A

USP and NF chemical grade

Question 27

Q

Basic unit for mass:

Gram
Kilogram
Mole
Pound

Answer

A

Kilogram

BASE QUANTITY
1. Length (meter)
2. Mass (kilogram)
3. Time (second)
4. Electric current (ampere)
5. Thermodynamic temperature (Kelvin)
6. Amount of substance (mole)
7. Luminous intensity (Candela)

Question 28

Q

Which of the following is NOT A COLLIGATIVE PROPERTY of solutions?

pH
Freezing point
Osmotic pressure
Vapor pressure

Answer

A

pH

The properties of osmotic pressure, vapor pressure, freezing point, and boiling point are called COLLIGATIVE PROPERTIES.

When a solute is dissolved in a solvent, these colligative properties change in a predictable manner for each osmole of substance present:
 FREEZING POINT IS LOWERED by −1.86°C
 VAPOR PRESSURE IS LOWERED by 0.3 mm Hg or torr
 OSMOTIC PRESSURE IS INCREASED by a factor of 1.7 × 104 mm Hg or torr
 BOILING POINT IS RAISED by 0.52°C

Question 29

Q

Most clinical microbiology laboratories are categorized at what biosafety level?

1
2
3
4

Question 30

Q

Degree of hazard #2:

Slight
Moderate
Serious
Extreme

Answer

A

Moderate

DEGREE OF HAZARD
0: NO OR MINIMAL
1: SLIGHT
2: MODERATE
3: SERIOUS
4: EXTREME

Question 31

Q

Electrical equipment fire:

Class A
Class B
Class C
Class D

Answer

A

Class C

Fires have been divided into four classes based on the nature of the combustible material and requirements for extinguishment:

Class A: ordinary combustible solid materials, such as paper, wood, plastic, and fabric

Class B: flammable liquids/gases and combustible petroleum products

Class C: energized electrical equipment

Class D: combustible/reactive metals, such as magnesium, sodium, and potassium

Question 32

Q

Type of extinguisher for CLASS A FIRES: 1. Pressurized water 2. Dry chemical 3. Carbon dioxide 4. Halon

1 and 2
1 and 3
1, 2 and 3
Only 1

Answer

A

1 and 2

TYPE OF EXTINGUISHER (Bishop page 47)
Class A: Pressurized water and dry chemical
Class B: Dry chemical and carbon dioxide
Class C: Dry chemical, carbon dioxide and halon
Class D: Metal X

Question 33

Q

All of the following are CRYOGENIC MATERIALS HAZARDS, EXCEPT:

Asphyxiation
Fire or explosion
Shock
Tissue damage similar to thermal burns

Answer

A

Shock

Liquid nitrogen is probably one of the most widely used cryogenic fluids (liquefied gases) in the laboratory.

There are, however, several hazards associated with the use of any cryogenic material: fire or explosion, asphyxiation, pressure buildup, embrittlement of materials, and tissue damage similar to that of thermal burns.

Question 34

Q

Repetitive strain disorders such as tenosynovitis, bursitis, and ganglion cysts:

Captionless Image
Cryogenic materials hazards
Electrical hazards
Ergonomic hazards
Mechanical hazards

Answer

A

ERGONOMIC HAZARDS

The primary contributing factors associated with repetitive strain disorders are position/posture, applied force, and frequency of repetition.

Remember to consider the design of hand tools (e.g., ergonomic pipets), adherence to ergonomically correct technique, and equipment positioning when engaging in any repetitive task. Chronic symptoms of pain, numbness, or tingling in extremities may indicate the onset of repetitive strain disorders. Other hazards include acute musculoskeletal injury. Remember to lift heavy objects properly, keeping the load close to the body and using the muscles of the legs rather than the back. Gradually increase force when pushing or pulling, and avoid pounding actions with the extremities.

Question 35

Q

The first step to take when attempting to repair electronic equipment is to:

Check all electronic connections
Turn instrument off and unplug it
Reset all the printed circuit boards
Review instrument manual

Answer

A

Turn instrument off and unplug it

Before REPAIR OR ADJUSTMENT of electrical equipment
The following should be done
(1) unplug the equipment
(2) make sure the hands are dry
(3) remove jewelry.

Question 36

Q

When a person is receiving an electrical shock, all of the following should be done EXCEPT:

Pull the person away from the electrical source
Turn off the circuit breaker
Move the electrical source using a glass object
Move the electrical source using a wood object

Answer

A

Pull the person away from the electrical source

When an accident involving electrical shock occurs:
The electrical source must be removed immediately. TURNING OFF THE CIRCUIT BREAKER, UNPLUGGING THE EQUIPMENT, or moving the equipment using a nonconductive glass or wood object are safe procedures to follow.

Question 37

Q

Most common source of light for work in the visible and near-infrared regions:

Deuterium discharge lamp and mercury arc lamp
Incandescent tungsten or tungsten-iodide lamp

Answer

A

Incandescent tungsten or tungsten-iodide lamp

The most common source of light for work in the visible and near-infrared regions is the incandescent tungsten or tungsten-iodide lamp.

Question 38

Q

The lamps most commonly used for ultraviolet (UV) work are:

Deuterium discharge lamp and mercury arc lamp
Incandescent tungsten or tungsten-iodide lamp

Answer

A

Deuterium discharge lamp and mercury arc lamp

The lamps most commonly used for ultraviolet (UV) work are the deuterium discharge lamp and the mercury arc lamp.

Question 39

Q

Which is the most sensitive detector for spectrophotometry?

Photomultiplier
Phototube
Electron multiplier
Photodiode array

Answer

A

Photomultiplier

Because of this amplification, the PM tube is 200 times more sensitive than the phototube. PM tubes are used in instruments designed to be extremely sensitive to very low light levels and light flashes of very short duration.

Question 40

Q

Reflectance spectrometry uses which of the following?

Luminometer
Tungsten–halogen lamp
Photomultiplier tube
UV lamp
Thermometer to monitor temperature in reaction

Answer

A

Tungsten–halogen lamp

Slide technology depends on reflectance spectrophotometry.

For colorimetric determinations, the light source is a tungsten–halogen lamp.

Question 41

Q

Which of the following light sources is used in atomic absorption spectrophotometry?

Hollow-cathode lamp
Xenon arc lamp
Tungsten light
Deuterium lamp
Laser

Answer

A

Hollow-cathode lamp

The usual light source, known as a hollow-cathode lamp, consists of an evacuated gas-tight chamber containing an anode, a cylindrical cathode, and an inert gas, such as helium or argon.

Question 42

Q

Used to measure concentration of LARGE PARTICLES: 1. Nephelometry 2. Turbidimetry 3. Absorption spectroscopy

1 only
2 only
1 and 2
1, 2 and 3

Answer

A

1 and 2

Nephelometry and turbidimetry are used to measure the concentrations of large particles (such as antigen–antibody complexes, prealbumin, and other serum proteins) that because of their size cannot be measured by absorption spectroscopy.

Question 43

Q

Temperature is _______ proportional to fluorescence.

Directly proportional
Inversely proportional
No effect

Answer

A

Inversely proportional

Question 44

Q

Low temperature:

Increase in fluorescence
Decrease in fluorescence

Answer

A

Increase in fluorescence

Question 45

Q

Which of the following techniques measures light scattered and has a light source placed at 90 degrees from the incident light?

Chemiluminescence
Atomic absorption spectrophotometry
Nephelometry
Turbidimetry

Answer

A

Nephelometry

Question 46

Q

Which of the following instruments is used in the clinical laboratories to detect beta and gamma emissions?

Fluorometer
Nephelometer
Scintillation counter
Spectrophotometer

Answer

A

Scintillation counter

Question 47

Q

Liquids (reagents, diluents, and samples) are pumped through a system of [continuous] tubing:

Continuous flow analysis
Centrifugal analysis
Discrete analysis
None of these

Answer

A

Continuous flow analysis

Question 48

Q

Which of the following types of analyzers offers RANDOM-ACCESS CAPABILITIES?

Discrete analyzers
Continuous-flow analyzers
Centrifugal analyzers
None of these

Answer

A

Discrete analyzers

All three can use batch analysis (i.e., large number of specimens in one run), but only discrete analyzers offer random-access, or stat, capabilities.

Question 49

Q

Checking instrument calibration, temperature accuracy, and electronic parameters are part of:

Preventive maintenace
Quality control
Function verification
Precision verification

Answer

A

Function verification

Function verification includes monitoring temperature, setting electronic parameters, calibrating instruments and analyzing control data.

Question 50

Q

LEASE CHECK THREE (3) BOXES: Measures of center.

Coefficient of variation
Mean
Median
Mode
Range
Standard deviation

Answer

A

Mean
Median
Mode

The three most commonly used descriptions of the center of a dataset are the mean, the median, and the mode.

Question 51

Q

PLEASE CHECK THREE (3) BOXES: Measures of spread.

Coefficient of variation
Mean
Median
Mode
Range
Standard deviation

Answer

A

Coefficient of variation
Range
Standard deviation

The spread represents the relationship of all the data points to the mean. There are three commonly used descriptions of spread: (1) range (2) standard deviation (SD), and (3) coefficient of variation (CV).

Question 52

Q

Systematic errors include: PLEASE CHECK 3 BOXES.

Calibrator reconstitution
Electro-optical mechanism
Environmental conditions
Fluctuations in line voltage
Instability of instrument
Reagent dispensing
Reagent lot variability
Sample evaporation
Temperature of analyzer
Variation in handling techniques: pipetting, mixing, timing
Variation in operators
Wear and tear of instrument

Answer

A

Fluctuations in line voltage
Reagent lot variability
Wear and tear of instrument

A SYSTEMATIC ERROR, on the other hand, will be seen as a trend in the data. Control values gradually rise (or fall) from the previously established limits. This type of error includes improper calibration, deterioration of reagents, sample instability, instrument drift, or changes in standard materials. All the Westgard rules that indicate trends identify systematic errors. 2(2S), 4(1S) and 10(x) rule.

SYSTEMATIC ERRORS MAY BE DUE TO:
Aging reagents
Aging calibrators
Instrument components
Optical changes
Fluctuations in line voltage
Wear and tear of instrument
Reagent lot variability
Calibration differences
Technologist interactions

Question 53

Q

Random errors include: PLEASE CHECK 3 BOXES.

Aging reagents
Aging calibrators
Calibration differences
Instrument components
Fluctuations in line voltage
Optical changes
Reagent lot variability
Reagent dispensing
Technologist interactions
Variation in handling techniques: pipetting, mixing, timing
Variation in operator
Wear and tear of instrument

Answer

A

Reagent dispensing
Variation in handling techniques: pipetting, mixing, timing
Variation in operator

RANDOM ERROR is one with no trend or means of predicting it. Random errors include such situations as mislabeling a sample, pipetting errors, improper mixing of sample and reagent, voltage fluctuations not compensated for by instrument circuitry, and temperature fluctuations. Violations of the 1(2S), 1(3S) and R(4S) Westgard rules are usually associated with random error. To assess the situation, the sample is assayed using the same reagents. If a random error occurred, the same mistake may not be made again, and the result will be within appropriate control limits.

RANDOM ERRORS MAY BE DUE TO:
Reagent dispensing
Sample evaporation
Temperature of analyzer
Electro-optical mechanism
Calibrator reconstitution
Environmental conditions
Instability of instrument
Variation in handling techniques: pipetting, mixing, timing
Variation in operators

Question 54

Q

Most frequently occurring value in a dataset:

Mean
Median
Mode
Range

Answer

A

Mode

The mode is the most frequently occurring value in a dataset. Although it is seldom used to describe data, it is referred to when in reference to the shape of data, a bimodal distribution, for example.

Question 55

Q

Type of systemic error in the sample direction and magnitude; the magnitude of change is constant and not dependent on the amount of analyte.

Constant systematic error
Proportional systematic error

Answer

A

Constant systematic error

Constant error: Type of systemic error in the sample direction and magnitude; the magnitude of change is constant and not dependent on the amount of analyte.

Proportional error: Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration.

Question 56

Q

Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration.

Constant systematic error
Proportional systematic error

Answer

A

Proportional systematic error

Constant error: Type of systemic error in the sample direction and magnitude; the magnitude of change is constant and not dependent on the amount of analyte.

Proportional error: Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration.

Question 57

Q

Difference between the observed mean and the reference mean:

Bias
Confidence interval
Parametric method
Nonparametric method

Answer

A

Bias

Bias: Difference between the observed mean and the reference mean.

Negative bias indicates that the test values tend to be lower than the reference value, whereas positive bias indicates test values are generally higher.

Bias is a type of constant systematic error.

Question 58

Q

Ability of a test to detect a given disease or condition.

Analytic sensitivity
Analytic specificity
Diagnostic sensitivity
Diagnostic specificity

Answer

A

Diagnostic sensitivity

Analytic sensitivity: Ability of a method to detect small quantities of an analyte.

Analytic specificity: Ability of a method to detect only the analyte it is designed to determine.

Diagnostic sensitivity: Ability of a test to detect a given disease or condition.

Diagnostic specificity: Ability of a test to correctly identify the absence of a given disease or condition.

Question 59

Q

Ability of a test to correctly identify the absence of a given disease or condition.

Analytic sensitivity
Analytic specificity
Diagnostic sensitivity
Diagnostic specificity

Answer

A

Diagnostic specificity

Analytic sensitivity: Ability of a method to detect small quantities of an analyte.

Analytic specificity: Ability of a method to detect only the analyte it is designed to determine.

Diagnostic sensitivity: Ability of a test to detect a given disease or condition.

Diagnostic specificity: Ability of a test to correctly identify the absence of a given disease or condition.

Question 60

Q

Ability of a method to detect small quantities of an analyte.

Analytic sensitivity
Analytic specificity
Diagnostic sensitivity
Diagnostic specificity

Answer

A

Analytic sensitivity

Analytic sensitivity: Ability of a method to detect small quantities of an analyte.

Analytic specificity: Ability of a method to detect only the analyte it is designed to determine.

Diagnostic sensitivity: Ability of a test to detect a given disease or condition.

Diagnostic specificity: Ability of a test to correctly identify the absence of a given disease or condition.

Question 61

Q

Ability of a method to detect only the analyte it is designed to determine.

Analytic sensitivity
Analytic specificity
Diagnostic sensitivity
Diagnostic specificity

Answer

A

Analytic specificity

Analytic sensitivity: Ability of a method to detect small quantities of an analyte.

Analytic specificity: Ability of a method to detect only the analyte it is designed to determine.

Diagnostic sensitivity: Ability of a test to detect a given disease or condition.

Diagnostic specificity: Ability of a test to correctly identify the absence of a given disease or condition.

Question 62

Q

Positive predictive value:

Ability of a test to detect a given disease or condition.
Ability of a test to correctly identify the absence of a given disease or condition.
Chance of an individual having a given disease or condition if the test is abnormal.
Chance an individual does not have a given disease or condition if the test is within the reference interval.

Answer

A

Chance of an individual having a given disease or condition if the test is abnormal.

Positive predictive value: Chance of an individual having a given disease or condition if the test is abnormal.

Negative predictive value: Chance an individual does not have a given disease or condition if the test is within the reference interval.

Question 63

Q

Negative predictive value:

Ability of a test to detect a given disease or condition.
Ability of a test to correctly identify the absence of a given disease or condition.
Chance of an individual having a given disease or condition if the test is abnormal.
Chance an individual does not have a given disease or condition if the test is within the reference interval.

Answer

A

Chance an individual does not have a given disease or condition if the test is within the reference interval.

Question 64

Q

What percentage of values will fall between ±2 s in a Gaussian (normal) distribution?

34.13%
68.26%
95.45%
99.74%

Answer

A

95.45%

68.26% will lie within ±1 s
95.45% will lie within ±2 s
99.74% will lie within ±3 s

Answer 60

A

2:2S

Westgard multirule is a control procedure that utilizes control rules to assess numerical quality control data; the control rules establish the limits for data rejection in a system with two controls. Other rules apply when three controls are used.

1:2s = 1 control value exceeds the mean ±2 standard deviations; warning rule that triggers inspection of control values using the other rejection rules that follow; only rule that is not used to reject a run; results are reportable

1:3s = 1 control value exceeds the mean ±3 standard deviations; detects random error

2:2s = 2 consecutive control values exceed the same 2 standard deviation limit (same mean +2 s or same mean -2 s); detects systematic error

R:4s = 1 control value in a group exceeds the mean +2 s and a second control value exceeds the mean -2 s, creating a 4 standard deviation spread; detects random error

4:ls = 4 consecutive control values are recorded on one side of the mean and exceed either the same mean +1 s or the same mean -1 s; detects systematic error

10:x =10 consecutive control values are recorded on one side of the mean (either above or below the mean); detects systematic error

Answer 61

A

Two controls in the same run are greater than 4s units apart

The R:4s rule is applied to two control levels within the same run. The rule is violated when the algebraic difference between them (level 1 –
level 2) exceeds 4s.

The R:4s rule detects random error (error due to poor precision).

Answer 62

A

Systematic error

Systemic error: Error always in one direction.
Random error: Error varies from sample to sample.

Answer 63

A

Random error

Random errors are deviations from the true value caused by unavoidable errors inherent in laboratory measurements.

The standard error of the mean is a statistical concept reflecting sampling variation. It is the standard deviation of the entire population.

Parametric statistics refer to a Gaussian (normal) distribution of data.

Nonparametric statistics are more general and require no assumptions.

Answer 64

A

Deterioration of the reagent

Answer 65

A

Levy–Jennings

The Levy–Jennings plot is a graph of all QC results with concentration plotted on the y axis and run number on the x axis.

Answer 66

A

Tonks–Youden

The Tonks–Youden plot is used for interlaboratory comparison of monthly means. The method mean for level 1 is at the center of the y axis and mean for level 2 at the center of the x axis. Lines are drawn from the means of both levels across the graph, dividing it into four equal quadrants. If a laboratory’s monthly means both plot in the lower left or upper right, then systematic error (SE) exists in its method.

Answer 67

A

Cusum

Cusum points are the algebraic sum of the difference between each QC result and the mean. The y axis is the sum of differences and the x axis is the run number. The center of the y axis is 0. Because QC results follow a random distribution, the points should distribute about the zero line. Results are out of control when the slope exceeds 45° or a decision limit (e.g., ±2.7s) is exceeded.

Answer 68

A

Accuracy

The accuracy of an analytical result is the closeness with which the measured value agrees with the true value.

Precision is reproducibility.

Accuracy and precision are independent, but it is the goal of the clinical laboratory to design methods that are both precise and accurate.

Answer 69

A

Precision

Accuracy is easy to define but difficult to establish and maintain.

Precision is relatively easy to measure and maintain.

Answer 70

A

Reliability

The reliability of an analytical procedure is its ability to maintain accuracy and precision over an extended period of time during which supplies, equipment, and personnel in the laboratory may change. It is often used interchangeably with the term “consistency.” It is the goal of every clinical laboratory to produce reliable results.

Answer 71

A

Student’s t test

T TEST: COMPARES MEANS, ACCURACY
F TEST: COMPARES S.D., PRECISION

Student’s t test is the ratio of mean difference to the standard error of the mean difference (bias/random error) and tests for a significant difference in means.

The F test is the ratio of variances and determines if one method is significantly less precise.

Answer 72

A

120 minutes (2 hours)

Answer 73

A

5 to 15 mg/dL

Glucose measurements can be 5 to 15 mg/dL erroneously higher by reducing methods than by more accurate enzymatic methods.

Answer 74

A

Glucose oxidase

Glucose oxidase is the most specific enzyme reacting with only beta D-glucose. Glucose oxidase converts beta D-glucose to gluconic acid.

Mutarotase may be added to the reaction to facilitate the conversion of alpha-D-glucose to beta-D-glucose.

Answer 75

A

Glucose-6-phosphate dehydrogenase

The hexokinase method is considered more accurate than the glucose oxidase methods because the coupling reaction using glucose-6-phosphate dehydrogenase is highly specific; therefore, it has less interference than the coupled glucose oxidase procedure.

Answer 76

A

Hemolysis

Hemolyzed samples require a serum blank correction (subtraction of the reaction rate with hexokinase omitted from the reagent).

Answer 77

A

False decrease

Generally accepted as the reference method, hexokinase method is not affected by ascorbic acid or uric acid. Gross hemolysis and extremely elevated bilirubin may cause a false decrease in results.

Answer 78

A

Type 1 diabetes mellitus

Answer 79

A

Type 2 diabetes mellitus

Answer 80

A

Data represents an impaired glucose status

Resting plasma glucose
NORMAL <140
IMPAIRED 140 – 199
DIAGNOSTIC ≥ 200 mg/dL

Fasting plasma glucose
NORMAL <100
IMPAIRED 100 – 125
DIAGNOSTIC ≥ 126 mg/dL

2-hour OGTT
NORMAL <140
IMPAIRED 140 – 199
DIAGNOSTIC ≥ 200 mg/dL

HbA1c
NORMAL <5.7 %
IMPAIRED 5.7 – 6.4%
DIAGNOSTIC ≥ 6.5%

Answer 81

A

6.5%

If the result is 6.5% or more, the treatment plan should be adjusted to achieve a lower level, and the test performed every 3 months until control is improved.

Answer 82

A

Red blood cell life span

Two factors determine the glycosylated hemoglobin levels: the average glucose concentration and the red blood cell life span.

If the red blood cell life span is decreased because of another disease state such as hemoglobinopathies, the hemoglobin will have less time to become glycosylated and the glycosylated hemoglobin level will be lower.

Answer 83

A

Glycosylated hemoglobin (HbA1c)

Long-term estimation of glucose concentration can be followed by measuring glycosylated hemoglobin (Hb A1c). A level of 8% or less is considered “good” glycemic control.

Because the average red blood cell lives approximately 120 days, the glycosylated hemoglobin level at any one time reflects the average blood glucose level over the previous 2 to 3 months. Therefore, measuring the glycosylated hemoglobin provides the clinician with a time-averaged picture of the patient’s blood glucose concentration over the past 3 months.

Answer 84

A

Fructosamine

FRUCTOSAMINE: GLYCOSYLATED ALBUMIN

Fructosamine assays are the most widely used to assess short-term (3 to 6 weeks) glycemic control because the average half-life of the proteins is 2–3 weeks.

Answer 85

A

Gluconeogenesis

Glycolysis: Metabolism of glucose molecule to pyruvate or lactate for production of energy

Gluconeogenesis: Formation of glucose-6-phosphate from noncarbohydrate sources

Glycogenolysis: Breakdown of glycogen to glucose for use as energy

Glycogenesis: Conversion of glucose to glycogen for storage

Lipogenesis: Conversion of carbohydrates to fatty acids

Lipolysis: Decomposition of fat

Answer 86

A

Glucagon

Glucagon is the primary hormone responsible for increasing glucose levels. It is synthesized by the ALPHA-cells of islets of Langerhans in the pancreas and released during stress and fasting states.

ACTION OF GLUCAGON
Increases glycogenolysis: glycogen → glucose
Increases gluconeogenesis: fatty acids → acetyl-CoA → ketone, proteins → amino acids

Answer 87

A

Insulin

Insulin is the only hormone that decreases glucose levels and can be referred to as a hypoglycemic agent.

Insulin is the primary hormone responsible for the entry of glucose into the cell. It is synthesized by the beta cells of islets of Langerhans in the pancreas.

It decreases plasma glucose levels by increasing the transport entry of glucose in muscle and adipose tissue by way of nonspecific receptors. It also regulates glucose by increasing glycogenesis, lipogenesis, and glycolysis and inhibiting glycogenolysis.

ACTION OF INSULIN
Increases glycogenesis and glycolysis: glucose → glycogen → pyruvate → acetyl-CoA
Increases lipogenesis
Decreases glycogenolysis

Answer 88

A

Hyperglycemia

CORTISOL INCREASES BLOOD GLUCOSE.

Answer 89

A

Below 50 mg/dL

Answer 90

A

Type 1 DM

Answer 91

A

Type 2 DM

Answer 92

A

50 grams

ORAL LACTOSE TOLERANCE TESTS, measuring the increase in plasma glucose or galactose following ingestion of lactose, have been used to diagnose lactase deficiency.

Answer 93

A

Dilution = 2:10
Ratio = 2:8

Answer 94

A

Moles = g/MW

= 75g/ 58g/mol
= 1.29 moles
= 1.3 moles

Answer 95

A

all of the above

Answer 96

A

according to their chemical properties and classification

Answer 97

A

a. Impermeable lab coat with eye/ face protection and appropriate disposable gloves

Nitrile gloves used on organic chemicals

Answer 98

A

UV light and microwaves - BSC, Spectro

Most common UV light source - Mercury lamp/ deuterium lamp

UV in CC = VERY SHORT

Answer 99

A

b. Alert and evacuate those in the immediate area out of harms way

Answer 100

A

b. Nuclear magnetic resonance spectroscopy

Answer 101

A

tungsten light bulb

light source for UV spectrum: MXDHH
entrance slit: prevents stray light
exit slit: selects specific band pass

Answer 102

A

HAXI
horizontal axis/ x axis
abscissa
independent variable

VOYD
vertical axis/ ordinate
y-axis
dependent variable

Answer 103

A

Diabetes monitoring

Answer 104

A

fixed angle/ angle-head centri

swinging bucket/ horizontal-head centri = horizontal when rotating, vertical when at rest

most rapid = ultracentrifuge

Answer 105

A

presumptive test

Answer 106

A

definitive test

Answer 107

A

all of these

Answer 108

A

Calcium

Best = Total proteins

Answer 109

A

200mg/dl = clear
300mg/dl = turbid/ hazy
400mg/dl = lactascent
600mg/dl = MILKY/ OPAQUE

Answer 110

A

1, 2, 3, 4

Answer 111

A

1-2 hours

Answer 112

A

Diagnosis of monoclonal gammopathies

Answer 113

A

All of these

Answer 114

A

Proteinuria

Answer 115

A

Negatively, anode

Answer 116

A

BCG (Bromcresol green)

Answer 117

A

Bromcresol purple (BCP)

BCP is more specific for albumin than BCG.

Answer 118

A

Dehydration

Answer 119

A

Prolonged tourniquet application

Answer 120

A

Microalbuminuria

Answer 121

A

Glutamine

Glutamine is the most abundant amino acid in the body, being involved in more metabolic processes than any other amino acid.

Answer 122

A

Tyrosine

Tyrosine is a precursor of the adrenal hormones epinephrine, norepinephrine, and dopamine and the thyroid hormones, including thyroxine.

It is important in overall metabolism, aiding in the functions of the adrenal, thyroid, and pituitary glands.

Answer 123

A

Albumin

Albumin is responsible for nearly 80% of the colloid osmotic pressure (COP) of the intravascular fluid, which maintains the appropriate fluid balance in the tissue.

Answer 124

A

Prealbumin

A low prealbumin level is a sensitive marker of poor nutritional status.

When a diet is deficient in protein, hepatic synthesis of proteins is reduced, with the resulting decrease in the level of the proteins originating in the liver, including prealbumin, albumin, and β-globulins. Because prealbumin has a short half-life of approximately 2 days, it decreases more rapidly than do other proteins.

Answer 125

A

A decreased level of prealbumin

Answer 126

A

Prealbumin

Prealbumin is the transport protein for thyroxine and triiodothyronine (thyroid hormones); it also binds with retinol-binding protein to form a complex that transports retinol (vitamin A) and is rich in tryptophan.

Answer 127

A

Emphysema

Answer 128

A

Down syndrome

Conditions associated with an elevated AFP level include spina bifida, neural tube defects, abdominal wall defects, anencephaly (absence of the major portion of the brain), and general fetal distress.

Low levels of maternal AFP indicate an increased risk for Down syndrome and trisomy 18, while it is increased in the presence of twins and neural tube defects.

Answer 129

A

Alpha2-macroglobulin

In nephrosis, the levels of serum α2-macroglobulin may increase as much as 10 times because its large size aids in its retention. The protein is also increased in diabetes and liver disease.

Use of contraceptive medications and pregnancy increase the serum levels by 20%.

Answer 130

A

Alpha1-acid glycoprotein

α1-Acid Glycoprotein (Orosomucoid)
α1-Acid glycoprotein (AAG), a major plasma glycoprotein, is negatively charged even in acid solutions, a fact that gave it its name. This protein is produced by the liver and is an acute-phase reactant.

Answer 131

A

Beta2-microglobulin

β2-microglobulin is a single polypeptide chain that is the light chain component of human leukocyte antigens (HLAs). It is found on the surface of nucleated cells and is notably present on lymphocytes. Increased plasma levels of β2-microglobulin are associated with renal failure, lymphocytosis, rheumatoid arthritis, and systemic lupus erythematosus.

Answer 132

A

Fibronectin

Answer 133

A

Fetal fibronectin

Fetal fibronectin (fFN) is a glycoprotein used to help predict the short-term risk of premature delivery.

Answer 134

A

Crosslinked C-telopeptides (CTX)

Cross-linked C-telopeptides (CTXs) are proteolytic fragments of collagen I formed during bone resorption (turnover).

CTX is a biochemical marker of bone resorption that can be detected in serum and urine.

Answer 135

A

Beta-trace protein

β-Trace protein (BTP; synonym prostaglandin D synthase) is a 168–amino acid, low-molecular-mass protein in the lipocalin protein family. Recently, it was verified that BTP was established as an accurate marker of CSF leakage.

It has also been reported recently as a potential marker in detecting impaired renal function, although no more sensitive than cystatin C.

Answer 136

A

Cystatin C

Answer 137

A

Amyloid β42 (Aβ42) and Tau protein

In a symptomatic patient, low Aβ42 along with high Tau reflects an increased likelihood of Alzheimer disease, but it does not mean that the person definitely has Alzheimer disease. If a patient does not have abnormal levels of these proteins, then the dementia is more likely due to a cause other than Alzheimer disease.

Answer 138

A

Myoglobin

As a cardiac biomarker, myoglobin has been used in conjunction with troponin to help diagnose or rule out a heart attack. When striated muscle is damaged, myoglobin is released, elevating the blood levels.

In an AMI, this increase is seen within 2 to 3 hours of onset and reaches peak concentration in 8 to 12 hours. Myoglobin is a small molecule freely filtered by the kidneys, allowing levels to return to normal in 18 to 30 hours after the AMI.

Because of the speed of appearance and clearance of myoglobin, it is also a useful marker for monitoring the success or failure of reperfusion.

Answer 139

A

Troponin

ACUTE CORONARY SYNDROME/MYOCARDIAL INFARCTION

Cardiac troponin (cTn) represents a complex of regulatory proteins that include troponin I (cTnI) and troponin T (cTnT) that are specific to heart muscle.

cTnI and cTnT are the “gold standard” in the diagnosis of acute coronary syndrome (ACS). cTn should be measured in all patients presenting with symptoms suggestive of ACS, in conjunction with physical examination and ECG.

Answer 140

A

hs-CRP

HIGH-SENSITIVITY CRP
Considered a GOOD PREDICTOR TEST for assessing cardiovascular risk

CK-MB, TROPONIN AND MYOGLOBIN
Used to assess if a myocardial infarction HAS OCCURRED

Answer 141

A

B-type natriuretic peptide

B-type (brain) natriuretic peptide (BNP) is used to determine if physical symptoms are related to congestive heart failure.

Answer 142

A

BNP and echocardiogram

DIAGNOSIS OF CONGESTIVE HEART FAILURE:
Until recently, this condition was diagnosed strictly on the basis of symptomatology and/or as a result of procedures such as echocardiography, but more recently a biomarker for this condition is the brain form or B-type natriuretic peptide (BNP), which has been approved as a definitive test for this condition and appears to be an excellent marker for early heart failure.

Answer 143

A

Albumin cobalt binding

Albumin cobalt binding is a test that measures ischemia-modified albumin, which is a marker for ischemic heart disease.

Answer 144

A

Chylomicron

These chylomicrons enter the blood through the lymphatic system, where they impart a turbid appearance to serum.

Answer 145

A

Greater than 600 mg/dL

The appearance of the plasma or serum can be observed and noted after a minimum 12-hour fast.

If the plasma is clear, the triglyceride level is probably less than 200 mg/dL. When the plasma appears hazy or turbid, the triglyceride level has increased to greater than 300 mg/dL, and if the specimen appears
opaque and milky (lipemic, from chylomicrons), the triglyceride level is probably greater than 600 mg/dL.

Note:
1. Clear plasma: TAG < 200 mg/dL
2. Hazy or turbid plasma: TAG > 300 mg/dL
3. Opaque or milky plasma: TAG > 600 mg/dL

Answer 146

A

Total cholesterol, triglyceride, HDL cholesterol, LDL cholesterol

A “routine” lipid profile would most likely consist of the measurement of total cholesterol, triglyceride, HDL cholesterol, and LDL cholesterol.

Answer 147

A

In the fasting state, approximately 12 hours after eating

Blood specimens for lipid studies should be drawn in the fasting state at least 9 to 12 hours after eating. Although fat ingestion only slightly affects cholesterol levels, the triglyceride results are greatly affected. Triglycerides peak at about 4 to 6 hours after a meal, and these exogenous lipids should be cleared from the plasma before analysis.

Answer 148

A

Cholesterol

Total cholesterol screenings are commonly performed on nonfasting individuals.

Total cholesterol is only slightly affected by the fasting status of the individual, whereas triglycerides, fatty acids, and lipoproteins are greatly affected.

Answer 149

A

Lipase

It is first necessary to hydrolyze the triglycerides to free fatty acids
and glycerol. This hydrolysis step is catalyzed by the enzyme lipase.

The glycerol is then free to react in the enzyme-coupled reaction system that includes glycerokinase, pyruvate kinase, and lactate dehydrogenase or in the enzyme-coupled system that includes glycerokinase, glycerophosphate oxidase, and peroxidase.

Answer 150

A

Chylomicrons

Chylomicrons, which contain apo B-48, are the largest and the least dense of the lipoprotein particles.

HDL, the smallest and most dense lipoprotein particle, is synthesized by both the liver and the intestine.

Answer 151

A

HDL

Chylomicrons, which contain apo B-48, are the largest and the least dense of the lipoprotein particles.

HDL, the smallest and most dense lipoprotein particle, is synthesized by both the liver and the intestine.

Answer 152

A

LpX

Lipoprotein X is an abnormal lipoprotein present in patients with biliary cirrhosis or cholestasis and in patients with mutations in lecithin:cholesterol acyltransferase (LCAT), the enzyme that esterifies cholesterol.

Answer 153

A

Chylomicrons

From the epithelial cells, the chylomicrons are released into the lymphatic system, which transports chylomicrons to the blood. The chylomicrons may then carry the triglycerides to adipose tissue for storage, to organs for catabolism, or to the liver for incorporation of the triglycerides into very-low-density lipoproteins (VLDLs). Chylomicrons are normally cleared from plasma within 6 hours after a meal.

Answer 154

A

VLDL

VLDL transports the majority of endogenous triglycerides, while the triglycerides of chylomicrons are derived entirely from dietary absorption.

Answer 155

A

Cholesterol

The beta-lipoprotein fraction is composed of approximately 50% cholesterol, 6% triglycerides, 22% phospholipids, and 22% protein.

The beta-lipoproteins, which are also known as the low-density lipoproteins (LDLs), are the principal transport vehicle for cholesterol
in the plasma.

Answer 156

A

50%

About 50% of the weight of HDL is protein, largely apo A-I and apo A-II. The HDL is about 30% phospholipid and 20% cholesterol by weight.

Answer 157

A

High-density lipoproteins (HDLs)

The HDLs, also known as the alpha-lipoproteins, have the greatest density of 1.063-1.210 g/mL and move the fastest electrophoretically toward the anode.

Answer 158

A

Coronary artery disease

The quantification of the HDL cholesterol level is thought to contribute in assessing the risk that an individual may develop coronary artery disease (CAD).

There appears to be an inverse relationship between HDL cholesterol and CAD. With low levels of HDL cholesterol, the risk of CAD increases.

Answer 159

A

HDL-C concentration < 40 mg/dL

POSITIVE (INCREASED) RISK FACTORS
 Age: ≥ 45 y for men; ≥ 55 y or premature menopause for women
 Family history of premature CHD
 Current cigarette smoking
 Hypertension (blood pressure ≥ 140/90 mm Hg or taking antihypertensive medication)
 LDL-C concentration ≥ 160 mg/dL (≥ 4.1 mmol/L), with ≤ 1 risk factor
 LDL-C concentration ≥ 130 mg/dL (3.4 mmol/L), with ≥ 2 risk factors
 LDL-C concentration ≥ 100 mg/dL (2.6 mmol/L), with CH D or risk equivalent
 HDL-C concentration < 40 mg/dL (< 1.0 mmol/L)
 Diabetes mellitus = CH D risk equivalent
 Metabolic syndrome (multiple metabolic risk factors)

NEGATIVE (DECREASED) RISK FACTORS
 HDL-C concentration ≥ 60 mg/dL (≥ 1.6 mmol/L)
 LDL-C concentration < 100 mg/dL (< 2.6 mmol/L)

Answer 160

A

Apoprotein A-I

Apoprotein A-I and apo A-II are the principal apoproteins of HDL, and low apo A-I has a high correlation with atherosclerosis. Conversely, apo-B100 is the principal apoprotein of LDL, and an elevated level is a major risk factor in developing coronary heart disease.

Answer 161

A

Apo-B100

LDL primarily contains apo B-100 and is more cholesterol rich than other apo B–containing lipoproteins.

Note:
Apo-AI, Apo-AII = HDL
Apo-B100 = LDL, VLDL
Apo-B48 = chylomicrons

Answer 162

A

Triglyceride

The VLDL fraction is primarily composed of triglycerides and lesser amounts of cholesterol and phospholipids.

Answer 163

A

Heparin-manganese

Either a dextran sulfate-magnesium chloride mixture or a heparin sulfate-manganese chloride mixture may be used to precipitate the LDL and VLDL cholesterol fractions. This allows the HDL cholesterol fraction to remain in the supernatant.

Answer 164

A

Apoprotein A-I deficiency

Deficiency of apo A-I is seen in Tangier disease, a familial hypocholesterolemia.

Answer 165

A

210

Once the total cholesterol, triglyceride, and HDL cholesterol are known, LDL cholesterol can be quantified by using the Friedewald equation

LDL cholesterol = Total cholesterol — (HDL cholesterol + Triglyceride/5)

In this example, all results are in mg/dL:
LDL cholesterol
= 300 - (50 + 200/5)
= 300 - (90)
= 210 mg/dL

Answer 166

A

Triglycerides over 400 mg/dL

LDL cholesterol may be calculated or measured directly:

Friedewald formula
Indirect, not valid for triglycerides over 400mg/dL
LDL cholesterol = total cholesterol — [HDL cholesterol + triglyceride/5]
Homogeneous assay uses detergents to block HDL and VLDL from reacting with the dye to form a colored chromogen product. An enzymatic cholesterol analysis is performed with only LDL cholesterol able to react.

Answer 167

A

– Chylomicrons →β→pre-β→α +

Although pre-β lipoprotein is lower in density than β lipoprotein, it migrates faster on agarose or cellulose acetate owing to its more negative apoprotein composition.

LIPOPROTEINS
1. By electrophoresis
From the origin: chylomicrons > beta (LDL) > prebeta (VLDL) > alpha (HDL) Anode
———
2. By ultracentrifugation
From the least dense and largest: chylomicrons > VLDL > LDL > HDL most dense and smallest

Answer 168

A

B-VLDL

β-VLDL (‘floating β’ lipoprotein) is an abnormal lipoprotein that accumulates in type 3 hyperlipoproteinemia. It is richer in cholesterol than VLDL and apparently results from the defective catabolism of VLDL. The particle is found in the VLDL density range but migrates electrophoretically with or near LDL.

Answer 169

A

Lp(a)

Lp(a) has a density similar to LDL, but migrates similarly to VLDL on electrophoresis. Thus it can be detected when the d > 1.006 g/mL protein is examined electrophoretically. When Lp(a) is present in concentrations exceeding 20-30 mg/dL (i.e., when it contributes more than about 10 mg/dL to the LDL-C measurement) an additional band with pre-β mobility is also observed in the d > 1.006 kg/L fraction (hence the name sinking pre-β-lipoprotein).

Answer 170

A

Lp(a)

Lipoprotein (a) is an apolipoprotein that is more commonly referred to as Lp(a). Although it is related structurally to LDL, Lp(a) is considered
to be a distinct lipoprotein class with an electrophoretic mobility in the prebeta region.

Lp(a) is believed to interfere with the lysis of clots by competing with plasminogen in the coagulation cascade, thus increasing the likelihood of atherosclerotic cardiovascular

Answer 171

A

Elevated VLDL and presence of chylomicrons

BLOOD LIPOPROTEIN PATTERNS IN PATIENTS WITH HYPERLIPOPROTEINEMIA
Type I: Extremely elevated TG due to the presence of chylomicrons
Type IIa: Elevated LDL
Type IIb: Elevated LDL and VLDL
Type III: Elevated cholesterol, TG; presence of B-VLDL
Type IV: Elevated VLDL
Type V: Elevated VLDL and presence of chylomicrons

Answer 172

A

Pre-renal azotemia

Answer 173

A

Renal azotemia

Answer 174

A

Post-renal azotemia

Answer 175

A

The catabolism of proteins and amino acids

Urea is generated by deamination of amino acids. Most is derived from the hepatic catabolism of proteins. Uric acid is produced by the catabolism of purines. Oxidation of pyrimidines produces orotic acid.

Answer 176

A

Oxidation of creatine

Answer 177

A

Alkaline picrate

The classic Jaffe reaction involves complexing of creatinine with an alkaline picrate solution to produce a red complex (Janovski complex).

Answer 178

A

Creatinine

Answer 179

A

Cystatin C

Answer 180

A

Catabolism of purines

Uric acid is the principal product of purine (adenosine and guanosine) metabolism.

Answer 181

A

Ammonia

Severe liver disease is the most common cause of altered ammonia metabolism. Therefore the monitoring of ammonia levels may be used to determine prognosis.

Answer 182

A

Hepatic coma

Hepatic coma is caused by accumulation of ammonia in the brain as a result of liver failure. The ammonia increases central nervous system pH and is coupled to glutamate, a central nervous system neurotransmitter, forming glutamine. Blood and cerebrospinal fluid ammonia levels are used to distinguish encephalopathy caused by cirrhosis or other liver disease from nonhepatic causes and to monitor patients with hepatic coma.

Answer 183

A

Urea

UREA > AMINO ACIDS > URIC ACID > CREATININE > CREATINE > AMMONIA

Constituents in the plasma that contain the element nitrogen are categorized as being protein- or nonprotein-nitrogen compounds. The principal substances included among the nonprotein-nitrogen compounds are urea, amino acids, uric acid, creatinine, creatine, and ammonia.

Of these compounds, urea is present in the plasma in the greatest concentration, comprising approximately 45% of the nonprotein-nitrogen fraction.

Answer 184

A

2.14

BUN is multiplied by 2.14 to give the urea concentration in mg/dL.

Answer 185

A

64 mg/dL
30 x 2.14 = 64.2 mg/dL

When it is necessary to convert urea nitrogen values to urea, the concentration may be calculated easily by multiplying the urea nitrogen value by 2.14.

This factor is derived from the molecular mass of urea (60 daltons) and the molecular weight of its two nitrogen atoms (28):

Answer 186

A

Sodium fluoride

With the urease reagent systems for the quantification of urea, the use of sodium fluoride must be avoided because of its inhibitory effect on this system.

Answer 187

A

Urea

In the diacetyl method, acidic diacetyl reacts directly with urea to form a yellow-diazine derivative.

Answer 188

A

Diabetes mellitus

Diseases associated with elevated blood ammonia levels include Reye syndrome, renal failure, chronic liver failure, cirrhosis, and hepatic encephalopathy.

Answer 189

A

The patient had two cigarettes 15 minutes prior to blood draw.

Cigarette smoking by the patient is a significant source of ammonia contamination. It is recommended that patients do not smoke for several hours before a specimen is collected.

Answer 190

A

Glomerular filtration rate is decreased by at least 50%

The assay for urea is only a rough estimate of renal function and will not show any significant level of increased concentration until the glomerular filtration rate is decreased by at least 50%.

A more reliable single index of renal function is the test for serum creatinine. Contrary to urea concentration, creatinine concentration is relatively independent of protein intake (from the diet), degree of hydration, and protein metabolism.

Answer 191

A

Creatinine

The quantity of creatinine formed daily is a relatively constant amount because it is related to muscle mass.

Therefore, it has been customary to quantify the creatinine present in a 24-hour urine specimen as an index of the completeness of the collection.

Answer 192

A

Uric acid

Uric acid may be quantified by reacting it with phosphotungstic acid reagent in alkaline solution.

Answer 193

A

Chronic renal failure

As renal function continues to be lost over time, chronic renal failure develops. Chronic renal failure is manifested by loss of excretory function, inability to regulate water and electrolyte balance, and increased production of parathyroid hormone, all of which contribute to the abnormal laboratory findings. The decreased production of erythropoietin causes anemia to develop.

Answer 194

A

Uric acid

Gout is a pathological condition that may be caused by a malfunction of purine metabolism or a depression in the renal excretion of uric acid. Two of the major characteristics of gout are hyperuricemia and a deposition of uric acid as monosodium urate crystals in joints, periarticular cartilage, bone, bursae, and subcutaneous tissue.

Answer 195

A

Lesch-Nyhan syndrome

Lesch-Nyhan syndrome is an X-linked genetic disorder (seen only in males) caused by the complete deficiency of hypoxanthine-guanine phosphoribosyltransferase, an important enzyme in the biosynthesis of purines.

Answer 196

A

Uric acid

An increase in serum uric acid levels may be seen during chemotherapy for leukemia. The cause of this is the accelerated breakdown of cell nuclei in response to the chemotherapy.

Other proliferative disorders that may respond similarly are lymphoma, multiple myeloma, and polycythemia. It is important that serum uric acid be monitored during chemotherapy to avoid nephrotoxicity.

Answer 197

A

Biliverdin

It is biliverdin that is the immediate precursor of bilirubin formation. Mesobilirubinogen and urobilinogen represent intestinal breakdown products of bilirubin catabolism.

Answer 198

A

Azobilirubin

Diazo reagent is a mixture of sulfanilic acid, sodium nitrite, and hydrochloric acid. The mixing of sodium nitrite with hydrochloric acid forms nitrous acid, which in turn reacts with sulfanilic acid to form a diazonium salt. This diazotized sulfanilic acid mixture, when mixed with solubilized bilirubin, forms a red azobilirubin complex.

Answer 199

A

Uridine diphosphate glucuronyltransferase

In order for the bilirubin-albumin complex to reach the parenchymal cells of the liver, the complex must be transported from the sinusoids to the sinusoidal microvilli and into the parenchymal cell. The microsomal fraction of the parenchymal cell is responsible for the conjugation of bilirubin. It is here that bilirubin reacts with uridine diphosphate glucuronate in the presence of the enzyme uridine diphosphate glucuronyltransferase to form bilirubin diglucuronide

Answer 200

A

Urobilin

In the colon, a portion of the urobilinogen is oxidized by the action of microorganisms to urobilin, which is excreted in the feces as an orange-brown pigment.

Answer 201

A

Albumin

Albumin acts as the transport vehicle for unconjugated bilirubin in the blood, with each mole of albumin capable of binding two moles of bilirubin.

Answer 202

A

Jaundice

Jaundice may be caused by an increase in either the unconjugated or conjugated form of bilirubin. Such increases in bilirubin levels may be caused by prehepatic, hepatic, or posthepatic disorders.

Answer 203

A

Brain

Kernicterus refers to the accumulation of bilirubin in brain tissue that occurs with elevated levels of unconjugated bilirubin. This condition is most commonly seen in newborns with hemolytic disease resulting from maternal-fetal Rh incompatibility. Newborns afflicted with kernicterus will exhibit severe neural symptoms.

Answer 204

A

Urobilinogen

In the small intestine, urobilinogen is formed through the enzymatic reduction process of anaerobic bacteria on bilirubin.

Answer 205

A

Specimen refrigeration

Bilirubin will deteriorate when exposed to either white or UV light. This deterioration is also temperature sensitive. Thus, specimens for bilirubin analysis should be stored in the dark at refrigerator temperature until the assay can be performed.

Lipemia should be avoided, due to its interference with spectrophotometric analyses. Because hemoglobin reacts with diazo reagent, use of hemolyzed specimens should be avoided. Hemolysis will cause bilirubin results to be falsely low.

Answer 206

A

Delta

Four bilirubin fractions represented by Greek letters have been identified: unconjugated (alpha), monoconjugated (beta), diconjugated (gamma), and conjugated bilirubin covalently bound to albumin (delta).

Delta-bilirubin is normally present in low concentration in the blood, and it is known to react directly with diazotized sulfanilic acid. Increased serum levels of delta-bilirubin are associated with liver-biliary disease.

Answer 207

A

Spleen

The cells of the reticuloendothelial system are responsible for the removal of old red blood cells from the peripheral circulation. As the red blood cells reach the end of their 120-day life span, the specialized cells mainly of the spleen phagocytize the aged cells and convert the released hemoglobin into the excretory pigment bilirubin.

Answer 208

A

Insoluble in water

Direct bilirubin was so named because of its ability in the van den Bergh method to react directly with diazotized sulfanilic acid without the addition of alcohol. Such a direct reaction is possible because direct bilirubin is conjugated in the liver with glucuronic acid, thereby making it a polar, water-soluble compound. Because conjugated bilirubin is both water soluble and not protein bound, it may be filtered through the glomerulus and excreted in the urine of jaundiced patients.

Answer 209

A

Conjugated bilirubin

Because conjugated bilirubin is both water soluble and not protein bound, it may be filtered through the glomerulus and excreted in the urine of jaundiced patients.

Answer 210

A

Diazo

Ehrlich’s DIAZO REAGENT consists of sulfanilic acid, hydrochloric acid, and sodium nitrite.

Answer 211

A

Caffeine-sodium benzoate

Unlike direct bilirubin, indirect-reacting bilirubin is insoluble in deionized water and dilute hydrochloric acid. Indirect-reacting bilirubin must first be mixed with methanol or caffeine-sodium benzoate to solubilize it before proceeding with the diazo reaction.

Note:
EVELYN-MALLOY: methanol
JENDRASSIK-GROF: caffeine-sodium benzoate

Answer 212

A

Obstructive jaundice

“Obstructive jaundice” is a term applied to conditions in which the common bile duct is obstructed because of gallstone formation, spasm, or neoplasm. Such an obstruction blocks the flow of bile from the gallbladder into the small intestine. This impedance of bile flow will result in a backflow of bile from the gallbladder into the sinusoids of the liver and ultimately into the peripheral circulation. Because the liver is not initially involved and the disorder is of posthepatic origin, the increased levels of bilirubin in the blood are caused by the backflow of conjugated bilirubin.

Answer 213

A

Unconjugated serum bilirubin level increased

Hemolytic jaundice is also referred to as prehepatic jaundice. It is caused by excessive destruction of erythrocytes at a rate that exceeds the conjugating ability of the liver. As a result, increased levels of unconjugated bilirubin appear in the blood.

Answer 214

A

Deficiency in the bilirubin conjugation enzyme system

The enzyme uridine diphosphate glucuronyltransferase catalyzes the conjugation of bilirubin with glucuronic acid. In newborns, especially premature infants, this liver enzyme system is not fully developed or functional. Because of this deficiency in the enzyme system, the concentration of unconjugated bilirubin rises in the blood, because only the conjugated form may be excreted through the bile and urine. The increased levels of unconjugated bilirubin will cause the infant to appear jaundiced.

Generally, this condition persists for only a short period because the enzyme system usually becomes functional within several days after birth.

Answer 215

A

Gilbert syndrome

Gilbert syndrome is a preconjugation transport disturbance. In this disorder the hepatic uptake of bilirubin is defective because the transportation of bilirubin from the sinusoidal membrane to the microsomal region is impaired.

Answer 216

A

Deficiency of the enzyme system required for conjugation of bilirubin

Both Crigler-Najjar syndrome and neonatal jaundice, a physiological disorder, are due to a deficiency in the enzyme-conjugating system. With a deficiency in uridine diphosphate glucuronyltransferase, the liver is unable to conjugate bilirubin, and both of these conditions are characterized by increased levels of unconjugated bilirubin.

Unlike Crigler-Najjar syndrome, which is a hereditary disorder, neonatal physiological jaundice is a temporary situation that usually corrects itself within a few days after birth.

Answer 217

A

Inability to conjugate bilirubin

In Dubin-Johnson syndrome, the transport of conjugated (direct) bilirubin from the microsomal region to the bile canaliculi is impaired. In this rare familial disorder, plasma conjugated bilirubin levels are increased because of defective excretion of bilirubin in the bile. Because conjugated bilirubin is water soluble, increased amounts of bilirubin are found in the urine.

Answer 218

A

Hepatic cirrhosis

Gamma spike: multiple myeloma
Beta-gamma bridging: hepatic cirrhosis
α1 globulin flat curve: juvenile cirrhosis (AATdeficiency)
Α2 globulin band spike: nephrotic syndrome
Spikes in α1, α2 and β: inflammation

Answer 219

A

Hepatitis

HEPATITIS: less than 80% liver damage
High: AST, ALT, LD, ALP, bilirubin
Normal: Total protein, albumin, ammonia

Answer 220

A

Cirrhosis

CIRRHOSIS: 80% liver tissue damage
Death of liver cells with regeneration leads to fibrosis, scarring and destruction of the normal liver architecture
Low: Total protein, albumin
High: Bilirubin, ammonia
Normal to slightly high: ALP
Normal: AST, ALT and LD

Answer 221

A

Cirrhosis

Cirrhosis is defined as destruction of the liver’s architecture.
The leading cause of this condition is alcohol abuse.

Answer 222

A

B1 and B2

Hemolytic jaundice: unconjugated bilirubin (B1)
Hepatic jaundice: unconjugated and conjugated bilirubin (B1 and B2)
Obstructive jaundice: conjugated bilirubin (B2)

Answer 223

A

Tissue damage and necrosis

The majority of serum enzymes that are of interest clinically are of intracellular origin. These enzymes function intracellularly, with only small amounts found in serum as a result of normal cellular turnover. Increased serum levels are due to tissue damage and necrosis, where the cells disintegrate and leak their contents into the blood. Thus, elevated serum levels of intracellular enzymes are used diagnostically to assess tissue damage.

Answer 224

A

Lower than expected

Factors that affect enzyme assays include temperature, pH, substrate concentration, and time of incubation. For each clinically important enzyme, the optimum temperature and pH for its specific reaction are known. When lower than optimum temperature or pH is employed, the measured enzyme activity will be lower than the expected activity value. As temperature increases, the rate of the reaction increases.

Answer 225

A

Enzymes are protein catalysts of biological origin.

Enzymes are protein in nature. Like all proteins, they may be denatured with a loss of activity as a result of several factors (e.g., heat, extreme pH, mechanical agitation, strong acids, and organic solvents). Enzymes act as catalysts for the many chemical reactions of the body. Enzymes increase the rate of a specific chemical reaction by lowering the activation energy needed for the reaction to proceed.

Answer 226

A

Lock-and-key theory by Emil Fischer

LOCK-AND-KEY (EMIL FISCHER)
The shape of the key (substrate) must fit into the lock (enzyme)

INDUCED-FIT (DANIEL KOSHLAND)
Substrate binding to the active site of the enzyme

Answer 227

A

First-order kinetics

In 1913, Michaelis and Menten hypothesized the role of substrate concentration in formation of the enzyme–substrate (ES) complex. According to their hypothesis, the substrate readily binds to free enzyme at a low-substrate concentration. With the amount of enzyme exceeding the amount of substrate, the reaction rate steadily increases as more substrate is added. The reaction is following first-order kinetics because the reaction rate is directly proportional to substrate concentration.

Eventually, however, the substrate concentration is high enough to saturate all available enzyme, and the reaction velocity reaches its maximum. When product is formed, the resultant free enzyme immediately combines with excess free substrate. The reaction is in zero-order kinetics, and the reaction rate depends only on enzyme concentration.

Answer 228

A

Zero-order kinetics

In 1913, Michaelis and Menten hypothesized the role of substrate concentration in formation of the enzyme–substrate (ES) complex. According to their hypothesis, the substrate readily binds to free enzyme at a low-substrate concentration. With the amount of enzyme exceeding the amount of substrate, the reaction rate steadily increases as more substrate is added. The reaction is following first-order kinetics because the reaction rate is directly proportional to substrate concentration.

Eventually, however, the substrate concentration is high enough to saturate all available enzyme, and the reaction velocity reaches its maximum. When product is formed, the resultant free enzyme immediately combines with excess free substrate. The reaction is in zero-order kinetics, and the reaction rate depends only on enzyme concentration.

Answer 229

A

Kinetic assay

One of two general methods may be used to measure the extent of an enzymatic reaction: (1) fixed-time and (2) continuous-monitoring or kinetic assay.

In the fixed time method, the reactants are combined, the reaction proceeds for a designated time, the reaction is stopped (usually by inactivating the enzyme with a weak acid), and a measurement is made of the amount of reaction that has occurred. The reaction is assumed to be linear over the reaction time; the larger the reaction, the more enzyme is present.
In continuous-monitoring or kinetic assays, multiple measurements, usually of absorbance change, are made during the reaction, either at specific time intervals (usually every 30 or 60 seconds) or continuously by a continuous- recording spectrophotometer.

Answer 230

A

Coenzyme

A nonprotein molecule, called a cofactor, may be necessary for enzyme activity. Inorganic cofactors, such as chloride or magnesium ions, are called activators. A coenzyme is an organic cofactor, such as nicotinamide adenine dinucleotide (NAD).

When bound tightly to the enzyme, the coenzyme is called a prosthetic group. The enzyme portion (apoenzyme), with its respective coenzyme, forms a complete and active system, a holoenzyme.

Answer 231

A

Activator

A nonprotein molecule, called a cofactor, may be necessary for enzyme activity. Inorganic cofactors, such as chloride or magnesium ions, are called activators. A coenzyme is an organic cofactor, such as nicotinamide adenine dinucleotide (NAD).

When bound tightly to the enzyme, the coenzyme is called a prosthetic group. The enzyme portion (apoenzyme), with its respective coenzyme, forms a complete and active system, a holoenzyme.

Answer 232

A

Transferases

There are six major classes of enzymes. The International Commission of Enzymes of the International Union of Biochemistry has categorized all enzymes into one of these classes: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Transferases are enzymes that catalyze the transfer of groups, such as amino and phosphate groups, between compounds. Transferases frequently need coenzymes, such as pyridoxal-5’-phosphate (P-5-P), for the amino transfer reactions. Aspartate and alanine aminotransferases, creatine kinase, and gamma-glutamyltransferase are typical examples.

Answer 233

A

Aldolase

Hydrolases are enzymes that split molecules with the addition of water—for example, amylase, lipase, alkaline phosphatase, acid phosphatase,
5’-nucleotidase, and trypsin. They do not usually require coenzymes but often need activators.

Aldolase and carbonic anhydrase are examples of the class of enzymes known as the lyases. Lyases are enzymes that split molecules between carbon-to-carbon bonds without the addition of water. The resulting products usually contain carbon double bonds.

Answer 234

A

Oxidoreductases

Answer 235

A

Ligases

In addition to naming enzymes, the IUB system identifies each enzyme by an EC numerical code containing four digits separated by decimal points. The first digit places the enzyme in one of the following six classes:
1. Oxidoreductases. Catalyze an oxidation–reduction reaction between two substrates
2. Transferases. Catalyze the transfer of a group other than hydrogen from one substrate to another
3. Hydrolases. Catalyze hydrolysis of various bonds
4. Lyases. Catalyze removal of groups from substrates without hydrolysis; the product contains double bonds
5. Isomerases. Catalyze the interconversion of geometric, optical, or positional isomers
6. Ligases. Catalyze the joining of two substrate molecules, coupled with breaking of the pyrophosphate bond in adenosine triphosphate (ATP) or a similar compound

Answer 236

A

Decreasing the activation energy

Enzymes catalyze physiologic reactions by lowering the activation energy level that the reactants (substrates) must reach for the reaction to occur.

Answer 237

A

Pernicious anemia and hemolytic disorders

The highest levels of total LD are seen in pernicious anemia and hemolytic disorders.

Answer 238

A

LD-5

LD-5 is the most labile isoenzyme. Loss of activity occurs more quickly at 4°C than at 25°C. Serum samples for LD isoenzyme analysis should be stored at 25°C and analyzed within 24 hours of collection.

Answer 239

A

Paget’s disease

Elevated ALP levels may be observed in various bone disorders. Perhaps the highest elevations of ALP activity occur in Paget’s disease (osteitis deformans). Other bone disorders include osteomalacia, rickets, hyperparathyroidism, and osteogenic sarcoma.

Answer 240

A

Bone disease

Increased serum creatine kinase (CK), formerly called creatine phosphokinase (CPK), values are caused primarily by lesions of cardiac muscle, skeletal muscle, or brain tissue. CK increases in the early stages of Duchenne-type progressive muscular dystrophy. Assays of total CK and CK isoenzymes are commonly used in the diagnosis of myocardial infarction. Hypothyroidism causes a moderate increase in CK values. Elevation of this enzyme also occurs after vigorous muscular activity, in cases of cerebrovascular accidents (stroke), and after repeated intramuscular injections.

Answer 241

A

Creatine kinase

To aid in the diagnosis of skeletal muscle disease, measurement of creatine kinase would be most useful. CK yields the most reliable information when skeletal muscle disease is suspected.

Other enzymes that are also useful to measure are aspartate aminotransferase and lactate dehydrogenase. Both of these enzymes will be moderately elevated, whereas CK is significantly increased.

Answer 242

A

CK, AST, LD

When an AMI occurs, CK is the first enzyme to become elevated in the blood, rising within 4 to 6 hours following chest pain. AST exhibits a
rise in the serum level within 6 to 8 hours. LD shows an increase in 8 to 12 hours following infarction.

Measurement of these three enzymes to assess acute myocardial infarction has been replaced by cardiac troponin, myoglobin, and CK-MB.

Answer 243

A

Cholinesterase

Normal serum levels of cholinesterase are quite high, reflecting its continual synthesis and release by the liver. Decreased values are considered abnormal.

Answer 244

A

Amylase

AMYLASE is the smallest enzyme, with a molecular weight of 50,000 to 55,000 Da. Because of its small size, it is readily filtered by the renal glomerulus and also appears in the urine.

Answer 245

A

G6PD

Macroenzymes are high-molecular-mass forms of the serum enzymes (ACP, ALP, ALT, AMY, AST, CK, GGT, LD, and LPS) that can be bound to either an immunoglobulin (macroenzyme type 1) or a nonimmunoglobulin substance (macroenzyme type 2).

Macroenzymes are usually found in patients who have an unexplained persistent increase of enzyme concentrations in serum. The presence of macroenzymes can also increase with increasing age.

Answer 246

A

HER-2/neu

Answer 247

A

Nuclear matrix protein

Answer 248

A

Potassium

Answer 249

A

Potassium

As the primary intracellular cation, potassium is an integral part of the transmission of nerve impulses. Movement of potassium across the nerve tissue membrane permits the neural signal to move down the nerve fiber. Potassium also seems to be involved in synaptic processes, where the impulse “jumps” from one nerve fiber to another.

Answer 250

A

Bicarbonate

Bicarbonate is the second most abundant anion in the extracellular fluid. It is a major component of the blood buffering system, accounts for 90% of total blood carbon dioxide, and maintains charge neutrality in the cell.

Answer 251

A

Magnesium

Answer 252

A

Calcium and magnesium

Electrolytes are an essential component in numerous processes, including:
1. Volume and osmotic regulation
(sodium [Na+], chloride [Cl−], potassium [K+])

Myocardial rhythm and contractility
(K+, magnesium [Mg2+], calcium [Ca2+])
Cofactors in enzyme activation
(e.g., Mg2+, Ca2+, zinc [Zn2+])
Regulation of adenosine triphosphatase (ATPase) ion pumps (Mg2+)
Acid–base balance
(bicarbonate HCO3−, K+, Cl−)
Blood coagulation
(Ca2+, Mg2+)
Neuromuscular excitability
(K+, Ca2+, Mg2+)
Production and use of ATP from glucose
(e.g., Mg2+, phosphate PO4−)

Answer 253

A

Bicarbonate, potassium and chloride

Answer 254

A

Potassium

Hemolysis of blood specimens because of physiological factors is often difficult to differentiate from hemolysis produced by the blood collection itself. In either case, the concentration of potassium will be increased in the serum because of the release of the very high level of intracellular potassium from the erythrocytes into the plasma.

When hemolysis is present, the serum concentrations of sodium, bicarbonate, chloride, and calcium will be decreased because their concentrations are lower in erythrocytes than in plasma.

Answer 255

A

Sodium

Na+ is the most abundant cation in the ECF, representing 90% of all extracellular cations, and largely determines the osmolality of the plasma.

Answer 256

A

Less than 135 mmol/L

Hyponatremia is defined as a serum/plasma level less than 135 mmol/L.

Hyponatremia is one of the most common electrolyte disorders in hospitalized and nonhospitalized patients.

Levels below 130 mmol/L are clinically significant. Hyponatremia can be assessed by the cause for the decrease or with the osmolality level.

Answer 257

A

Diuretic use

Causes Of Hyponatremia
1. Increased Sodium Loss
Hypoadrenalism
Potassium deficiency
Diuretic use
Ketonuria
Salt-losing nephropathy
Prolonged vomiting or diarrhea
Severe burns

Increased Water Retention
Renal failure
Nephrotic syndrome
Hepatic cirrhosis
Congestive heart failure
Water Imbalance
Excess water intake
SIADH
Pseudohyponatremia

Answer 258

A

Plasma/serum osmolality

Hyponatremia can also be classified according to plasma/serum osmolality.

Because Na+ is a major contributor to osmolality, both levels can assist in identifying the cause of hyponatremia.

There are three categories of hyponatremia—low osmolality, normal osmolality, or high osmolality. Most instances of hyponatremia occur with decreased osmolality.

Answer 259

A

Pseudohyponatremia

Pseudohyponatremia can occur when Na+ is measured using indirect ion-selective electrodes (ISEs) in a patient who is hyperproteinemic or hyperlipidemic. An indirect ISE dilutes the sample prior to analysis and as a result of plasma/serum water displacement; the ion levels are falsely decreased.

Answer 260

A

Urine osmolality

The measurement of urine osmolality is necessary to evaluate the cause of hypernatremia. With renal loss of water, the urine osmolality is low or normal. With extrarenal fluid losses, the urine osmolality is increased.

Answer 261

A

Hypernatremia

Any condition that increases water loss, such as fever, burns, diarrhea, or exposure to heat, will increase the likelihood of developing hypernatremia.

Answer 262

A

Potassium

Potassium (K+) is the major intracellular cation in the body, with a concentration 20 times greater inside the cells than outside.

Many cellular functions require that the body maintain a low ECF concentration of K+ ions. As a result, only 2% of the body’s total K+ circulates in the plasma. Functions of K+ in the body include regulation of neuromuscular excitability, contraction of the heart, ICF volume, and H+ concentration.

Answer 263

A

Vomiting

Causes Of Hypokalemia
1. Gastrointestinal Loss
Vomiting
Diarrhea
Gastric suction
Intestinal tumor
Malabsorption
Cancer therapy—chemotherapy, radiation therapy
Large doses of laxatives

Renal Loss
Diuretics—thiazides, mineralocorticoids
Nephritis
Renal tubular acidosis
Hyperaldosteronism
Cushing’s syndrome
Hypomagnesemia
Acute leukemia
Cellular Shift
Alkalosis
Insulin overdose
Decreased Intake

Answer 264

A

Alkalosis

CAUSES OF HYPERKALEMIA
1. Decreased Renal Excretion
Acute or chronic renal failure (GFR < 20 mL/min)
Hypoaldosteronism
Addison’s disease
Diuretics

Cellular Shift
Acidosis
Muscle/cellular injury
Chemotherapy
Leukemia
Hemolysis
Increased Intake
Oral or intravenous potassium replacement therapy
Artifactual
Sample hemolysis
Thrombocytosis
Prolonged tourniquet use or excessive fist clenching

Answer 265

A

Chloride

Chloride (Cl−) is the major extracellular anion.

It is involved in maintaining osmolality, blood volume, and electric neutrality.

In most processes, Cl− shifts secondarily to a movement of Na+ or HCO3 −.

Answer 266

A

Cystic fibrosis

Measuring the concentration of chloride in sweat is a commonly used diagnostic procedure for determining the disorder of cystic fibrosis (CF). The majority of patients with CF will present with increased concentrations of sodium and chloride in their sweat.

Answer 267

A

Bicarbonate

Bicarbonate is the second most abundant anion in the ECF. Total CO2 comprises the bicarbonate ion (HCO3−), H2CO3, and dissolved CO2, with HCO3− accounting for more than 90% of the total CO2 at physiologic pH.

Because HCO3− composes the largest fraction of total CO2, total CO2 measurement is indicative of HCO3− measurement.

Answer 268

A

Magnesium

Magnesium (Mg2+) is the fourth most abundant cation in the body and second most abundant intracellular ion. The average human body (70 kg) contains 1 mol (24 g) of Mg2+. Approximately 53% of Mg2+ in the body is found in bone, 46% in muscle and other organs and soft tissue, and less than 1% is present in serum and RBCs.

Answer 269

A

Hypomagnesemia

Hypomagnesemia is most frequently observed in hospitalized individuals in intensive care units (ICUs) or those receiving diuretic therapy or digitalis therapy.

These patients most likely have an overall tissue depletion of Mg2+ as a result of severe illness or loss, which leads to low serum levels. Hypomagnesemia is rare in nonhospitalized individuals.

Answer 270

A

Parathyroid hormone, vitamin D and calcitonin

Three hormones, PTH, vitamin D, and calcitonin, are known to regulate serum Ca2+ by altering their secretion rate in response to changes in ionized Ca2+.

Answer 271

A

50

Free ionized calcium normally accounts for about 50% of total serum calcium, with the remainder being made up of complexed calcium (about 10%) and calcium bound to proteins (about 40%).

Answer 272

A

Cresolphthalein complexone

Total serum calcium concentration is often determined by the spectrophotometric quantification of the color complex formed with cresolphthalein complexone.

Answer 273

A

Ammonium molybdate

Serum inorganic phosphate concentrations are determined most commonly by reacting with ammonium molybdate reagent. The molybdenum-phosphate complexes can be quantified at 340 nm. Alternately, treatment of the phosphomolybdate compound formed with a reducing agent leads to the formation of molybdenum blue, which can be measured spectrophotometrically.

Answer 274

A

Hypernatremia
Ketoacidosis
Lactic acidosis
Methanol, ethanol, ethylene glycol poisoning
Uremia/renal failure

An elevated AG may be caused by uremia/renal failure, which leads to PO4 and SO4 retention; ketoacidosis, as seen in cases of starvation or diabetes; methanol, ethanol, ethylene glycol, or salicylate poisoning; lactic acidosis; hypernatremia; and instrument error.

Low AG values are rare but may be seen with hypoalbuminemia (decrease in unmeasured anions) or severe hypercalcemia (increase in unmeasured cations).

Answer 275

A

Hypoalbuminemia
Hypercalcemia

Answer 276

A

Serum

Osmolality may be measured in serum or urine. Major electrolyte concentrations, mainly sodium, chloride, and bicarbonate, provide the largest contribution to the osmolality value of serum.

Plasma use is not recommended because osmotically active substances may be introduced into the specimen from the anticoagulant.

Answer 277

A

92

For monovalent cations or anions the contribution to osmolality is approximately 92%.

Other serum electrolytes, serum proteins, glucose, and urea contribute to the remaining 8%.

Answer 278

A

2(Na) + (glucose ÷ 18) + (BUN ÷ 2.8)

Answer 279

A

Ferritin

In adults the total body iron content averages 3-4 g. The majority of this iron is found in the active pool as an essential constituent of hemoglobin, with a much lesser amount being an integral component of myoglobin and a number of enzymes.

Approximately 25% of the body iron is found in inactive storage forms. The major storage form of iron is ferritin, with a lesser amount being stored as hemosiderin.

Answer 280

A

Lithium heparin; dry

Evacuated collection tubes are not appropriate for blood gases. While both dry (lyophilized) and liquid heparin are acceptable anticoagulants, the liquid form is not recommended because excessive amounts can dilute the sample and possibly alter the sample due to equilibration with room air.

Answer 281

A

pO2 and pH increase; pCO2 decreases

Note:
OPEN TUBE (ENTRY OF OXYGEN)
⬆️ Increased pO2
⬇️ Deceased pCO2 (H2CO3)
⬆️ Increased pH (ALKALINE)
CLOSED TUBE (OXYGEN UTILIZED BY CELLS)
⬇️ Decreased pO2
⬆️ Increased pCO2 (H2CO3)
⬇️ Decreased pH (ACIDIC)

Answer 282

A

pO2 decreases, pCO2 increases, pH decreases

Note:
OPEN TUBE (ENTRY OF OXYGEN)
⬆️ Increased pO2
⬇️ Deceased pCO2 (H2CO3)
⬆️ Increased pH (ALKALINE)
CLOSED TUBE (OXYGEN UTILIZED BY CELLS)
⬇️ Decreased pO2
⬆️ Increased pCO2 (H2CO3)
⬇️ Decreased pH (ACIDIC)

Answer 283

A

Bicarbonate/carbonic acid

Because of its high concentration in blood, the bicarbonate/carbonic acid pair is the most important buffer system in the blood. This buffer system is also effective in the lungs and in the kidneys in helping to regulate body pH.

The other buffers that also function to help maintain body pH are the phosphate, protein, and hemoglobin buffer systems.

Answer 284

A

20:1 ratio of bicarbonate to carbonic acid

When the ratio of the concentrations of bicarbonate to carbonic acid is 20:1, the pH is 7.4

Answer 285

A

Carbon dioxide

Answer 286

A

Will decrease pO2 by 7%

Fever will decrease pO2 by 7%
Fever will increase pCO2 by 3%

Answer 287

A

Will increase pCO2 by 3%

Fever will decrease pO2 by 7%
Fever will increase pCO2 by 3%

Answer 288

A

Kidney function

The role of the lungs and kidneys in maintaining pH is depicted with the Henderson-Hasselbalch equation.

The numerator (HCO3−) denotes kidney functions, and the denominator (pCO2) denotes lung function.

Answer 289

A

Lung function

The role of the lungs and kidneys in maintaining pH is depicted with the Henderson-Hasselbalch equation.

The numerator (HCO3−) denotes kidney functions, and the denominator (pCO2) denotes lung function.

Answer 290

A

Metabolic alkalosis

An excess of bicarbonate without a change in pCO2 will increase the ratio of bicarbonate to carbonic acid. Therefore, the pH will increase; that is, the plasma becomes more alkaline.

Answer 291

A

pH 7.66 HCO3- 22 mmol/L pCO2 20 mm Hg

TIPS FOR EVALUATING ACID-BASE DISORDERS
1. Look at the pH: determine if acidosis or alkalosis

Compare pCO2 and HCO3-

A. pCO2 going opposite to pH – RESPIRATORY
Abnormal pCO2 respiratory [↓pH ↑pCO2 respiratory acidosis] [↑pH ↓pCO2 respiratory alkalosis]

B. HCO3- going same direction as pH - METABOLIC
Abnormal HCO3- metabolic [↓pH ↓HCO3- metabolic acidosis] [↑ pH ↑ HCO3- metabolic alkalosis]

If pH is normal, full compensation occurred
If main compensatory mechanism kicked in, but pH still out of normal range, partial compensation has occurred

Answer 292

A

pH 7.25 HCO3- 15 mmol/L pCO2 37 mm Hg

Answer 293

A

Metabolic alkalosis

A pH above 7.45 corresponds with alkalosis. Both bicarbonate and pCO2 are elevated. Bicarbonate is the conjugate base and is under metabolic (renal) control, while pCO2 is an acid and is under respiratory control. Increased bicarbonate (but not increased CO2) results in alkalosis; therefore, the classification is metabolic alkalosis, partially compensated by increased pCO2.

Answer 294

A

pH, pCO2 and pO2

pH, pCO2, and pO2 are measured directly from the specimen by utilizing electrodes. The pH and PCO2 electrodes are potentiometric where the voltage produced across a semipermeable membrane to hydrogen ions or CO2 gas is proportional to the “activity” of those ions in the patient’s sample. Activity is measured in voltage whose value can be presented in terms of concentration. pO2 is measured similarly, but using an amperometric electrode.

Note:
pH and pCO2 = POTENTIOMETRY
pO2 = AMPEROMETRY

Answer 295

A

Occasionally

Mixed respiratory and nonrespiratory disorders occasionally arise from more than one pathologic process and represent the most serious of medical conditions as compensation for the primary disorder is failing.

Answer 296

A

Respiratory acidosis

Answer 297

A

Pituitary gland

Answer 298

A

Anterior pituitary gland

Answer 299

A

Posterior pituitary gland

Answer 300

A

ACTH
FSH
LH
TSH

Answer 301

A

GH
Prolactin

Answer 302

A

GH

Growth hormone (GH), also called somatotropin, is structurally related to prolactin and human placental lactogen.

Answer 303

A

Oral glucose loading

Answer 304

A

Amino acids

Answer 305

A

Anterior pituitary gland

Answer 306

A

Vasopressin deficiency

Answer 307

A

TSH assay

TSH is produced by the anterior pituitary in response to low levels of free T4 or T3. A normal TSH rules out thyroid disease. TSH is low in primary hyperthyroidism and high in primary hypothyroidism.

Answer 308

A

Primary hyperthyroidism

In primary hyperthyroidism, the TSH will be within a range of 0–0.02 mU/mL, while in nonthyroid illnesses it will be 0.03 mU/mL or higher.

Answer 309

A

Primary hyperthyroidism

Answer 310

A

All of these

Answer 311

A

Aldosterone

Zona glomerulosa (G-zone) cells (outer 10%) synthesize mineralocorticoids (aldosterone) critical for sodium retention (volume), potassium, and acid–base homeostasis. They have low cytoplasmic-to-nuclear ratios and small nuclei with dense chromatin with intermediate lipid inclusions.

Answer 312

A

Cortisol

Zona fasciculata (F-zone) cells (middle 75%) synthesize glucocorticoids, such as cortisol and cortisone critical to blood glucose homeostasis and blood pressure.

Answer 313

A

Catecholamine

Medullary catecholamine products serve as firstresponders to stress by acting within seconds (cortisol takes 20 min) to promote the fight-or-flight response, which increases cardiac output and blood pressure, diverts blood toward muscle and brain, and mobilizes fuel from storage.

Answer 314

A

Excess secretion of pituitary ACTH

Cushing’s disease refers to adrenal hyperplasia resulting from misregulation of the hypothalamic–pituitary axis. It is usually caused by small pituitary adenomas. Cushing’s syndrome may be caused by Cushing’s disease, adrenal adenoma or carcinoma, ectopic ACTH-producing tumors, or excessive corticosteroid administration. The cause of Cushing’s syndrome can be differentiated using the ACTH and dexamethasone suppression tests.

Answer 315

A

Serum ACTH

Serum ACTH assays are very helpful in distinguishing the cause of Cushing’s syndrome. Patients with adrenal tumors have values approaching zero. Patients with ectopic ACTH tumors have values greater than 200 pg/dL. Fifty percent of patients with Cushing’s disease have high 8 a.m. ACTH levels (between 100–200 pg/dL). The high-dose dexamethasone suppression test is also used.

Answer 316

A

Overnight low-dose dexamethasone suppression test

Answer 317

A

Cholesterol

Answer 318

A

Estradiol (E2 )

Answer 319

A

Testosterone

Answer 320

A

Hirsutism

Answer 321

A

Acute toxicity

Answer 322

A

Chronic toxicity

Answer 323

A

Cigarette smokers

Cigarette smokers exhibit levels of 8-9% carboxyhemoglobin, but occasionally saturations of greater than 16% have been reported in heavy smokers.

Answer 324

A

Morphine

Heroin (diacetylmorphine), an abused drug, is a derivative of morphine. The morphine used in its synthesis is generally obtained from opium.

Answer 325

A

Marijuana

THC (tetrahydrocannabinol) is the principal active component of marijuana.

Answer 326

A

Marijuana

Marijuana is stored in fatty tissue and is metabolized slowly.

In persons who use marijuana several times per week, cannabinoids can be detected several weeks after last use.

For chronic daily users, this extends to months after discontinuation.

Answer 327

A

0.5 to 1 hour

The half-life of the circulating cocaine is brief: 0.5 to 1 hour. BISHOP

Answer 328

A

Cocaine

Cocaine is an abused drug and not available for therapeutic use. After absorption, cocaine in the blood is rapidly converted into ecgonine and benzoylecgonine.

Answer 329

A

Cocaine

CNS STIMULANTS
Cocaine and its metabolite, benzoylecgonine, and amphetamines and methamphetamines

CNS DEPRESSANTS
Barbiturates; methaqualone; benzodiazepines including Valium; and oxycodone and other opiates, including morphine, heroin (which metabolizes to morphine), codeine (methylmorphine), and methadone

HALLUCINOGENS OR PSYCHOACTIVES
Cannabinoids and phencyclidine (PCP)

ANTIDEPRESSANTS
Lithium, tricyclic antidepressants

Answer 330

A

Whole blood

After absorption, lead is distributed into an active pool in the blood and soft tissue and a storage pool in bone, teeth, and hair. In blood, the majority is found in erythrocytes, with only minor quantities in plasma or serum. Lead is mainly excreted by the kidney; hence urine or whole blood would be appropriate specimens for determining lead exposure.

Answer 331

A

Arsenic

ARSENIC
Toxins may BIND SULFHYDRYL GROUPS IN KERATIN FOUND IN HAIR AND FINGERNAILS

Answer 332

A

Cyanide overdose

The principal symptoms of cyanide overdose are tachypnea (initially), followed by respiratory depression and cyanosis, hypotension, convulsions, and coma. Death may occur in a matter of minutes because cyanide is a fast-acting toxin. Diagnosis may be difficult, and a high index of suspicion is needed to make the correct diagnosis.

Clues include the odor of bitter almonds, the occurrence of an altered mental status and tachypnea in the absence of cyanosis, and an unexplained metabolic acidosis (with an increased anion gap).

Answer 333

A

Arsenic toxicity

ODOR OF BITTER ALMONDS: CYANIDE POISONING

ODOR OF GARLIC, METALLIC TASTE: ARSENIC POISONING

Answer 334

A

Ethanol

Ethanol is probably the most common drug of abuse and is frequently responsible for the presentation of patients with altered mental status to hospitals and emergency rooms.

Answer 335

A

LADME: Liberation, absorption, distribution, metabolism and excretion

Liberation is the release of the drug
Absorption is the transport of drug from the site of administration to the blood
Distribution refers to the delivery of the drug to the tissues
Metabolism is the process of chemical modification of the drug by cells
Excretion is the process by which the drug and its metabolites are removed from the body

Answer 336

A

Varies with the drug, depending on its rate of absorption

The peak concentration of a drug is the highest concentration obtained in the dosing interval.

For oral drugs, the time of peak concentration is dependent upon their rates of absorption and elimination and is determined by serial blood measurements. Peak levels for oral drugs are usually drawn 1–2 hours after administration of the dose. For drugs given intravenously, peak levels are measured immediately after the infusion is completed.

Answer 337

A

Shortly before drug administration

When peak levels of the drug are required, the blood sample must be drawn at a specified time after drug administration.

Trough levels are most reliably determined by collecting the blood sample before the next drug administration.

Answer 338

A

Intravenous

When a drug is administered intravenously, all the drug enters the bloodstream.

Answer 339

A

Salicylate

The Trinder reaction or modification is used almost routinely in the determination of salicylate and is based on the colorimetric reaction with ferric ions.

Answer 340

A

Liver

Paracetamol, also known as acetaminophen.

Hepatotoxicity is common in acetaminophen overdose. It is particularly important to be able to determine the acetaminophen serum level rapidly so that the elimination half-life of the drug can be estimated. Hepatic necrosis is more common when the half-life exceeds 4 hours and is very likely when it exceeds 12 hours.

Answer 341

A

Kidney

Tobramycin and gentamicin are examples of aminoglycoside antibiotics. Their use has been associated with both nephrotoxicity and ototoxicity.

Answer 342

A

Tacrolimus

Tacrolimus (Prograf) is an antibiotic that functions as an immunosuppressant in organ transplantation, especially in liver transplants.

Answer 343

A

Theophylline

Theophylline is a bronchodilator that is used to treat asthma. The therapeutic range is 10-20 ug/mL, and use must be monitored to avoid toxicity. Use of theophylline has been replaced where possible with beta-adrenergic agonists, which are available in the inhaled form.

Answer 344

A

3 and 4

Anti-asthmatic drugs, such as THEOPHYLLINE and THEOBROMINE, are used for treatment of neonatal breathing disorders or of respiratory conditions that affect adults or children, such as asthma.

Digoxin - cardiac glycoside, CHF
Phencyclidine - hallucinogen

Answer 345

A

Caffeine

Theophylline, a xanthine with bronchodilator activity, is widely used in the treatment of asthma. Because of its availability and potential toxicity, it can also be subject to accidental overdose. Chromatographic methods are effective in separating theophylline from caffeine and theobromine, which are two commonly occurring and potentially interfering xanthines.

However, most clinical thin-layer chromatographic methods are relatively insensitive to the xanthines, and suspected theophylline overdose should be confirmed by HPLC or immunoassay methods.

Answer 346

A

Lithium

Lithium is used in the treatment of manic depression. Because of the small difference between therapeutic and toxic levels in the serum, accurate measurements of lithium concentrations are essential.

Answer 347

A

Vancomycin

The major toxicities of vancomycin are red man syndrome, nephrotoxicity, and ototoxicity.

Red man syndrome is characterized by an erythemic flushing of the extremities.

The renal and hearing effects are similar to those of the aminoglycosides.

Answer 348

A

Ethosuximide (Zarontin)

HENRY:
Ethosuximide is the drug of choice for absence (petit mal) seizures unaccompanied by other types of seizures. It is preferred over valproic acid, at least initially, because hepatotoxicity is a rare but serious side effect of valproic acid.

Answer 349

A

1, 2 and 3

Most analgesics, such as salicylates, acetaminophen, and ibuprofen, do not require TDM because physicians and pharmacists are able to achieve and maintain therapeutic levels with standardized dosing intervals.

Because of the presumed safety of these medications, they are available without a prescription and sold as OVER-THE-COUNTER medications.

Answer 350

A

Osmolar gap

Answer 351

A

Phosphomolybdic acid
‘FoFo’

Aresenomolybdic acid = Nelson somogyi
O-toluidine = aromatic rings
Ferric chloride = inverse colorimetry (+) colorless

Obsolete = 6C, Inc 5-15mg/dl
Only non-obsolete = O-toluidine

Answer 352

A

Glycolysis (EMP)

glycogenolysis = glycogen to glucose
gluconeogenesis = form glucose from other substances (AA, glycerol, pyruvate)
glycogenesis = glucose to glycogen

Answer 353

A

FBS (8-12 hours fast)

75g OGTT = pregnant GDM

Answer 354

A

Transthyretin (prealbumin) transport thyroxine and retinol

Albumin = indicator of nutritional status
B-trace protein = indicator of CSF leakage
Transferrin = transport iron in ferric state

Answer 355

A

Blanking technique: REAGENT blank

Patient blank = hemolyzed, lipemic, icteric spx

Answer 356

A

Water

CO2 = Class B and C
Dry chemical = A, B, C
Halon = B and C
Metal X = D

Answer 357

A

B. migration of lymphocytes = chronic

a. inc capillary permeability = acute
c. release of haptoglobin = acute
d. CRP release (and SAA) = acute – inc 1000x

Answer 358

A

c. B-hCG
threatened abortion: placenta is still intact; vaginal bleeding

a. AFP - amniotic fluid not vaginal secretion; inc in spina bifida/ neural tube defect, dec in down syndrome
b. fetal fibronectin - dec when pregnant is threatened, inc in pregnancy; detect pre-term labor

Answer 359

A

c. fibronectin (also albumin)

Adiponectin = marker for obesity (dec levels)

Recent studies have shown an inverse correlation between body mass index and adiponectin values. Lower levels of adiponectin correlate with an increased risk of heart disease, type 2 diabetes, metabolic syndrome, and obesity

Answer 360

A

HDL

LDL - highest cholesterol content
VLDL - endogenous TAG
CM - exogenous TAG

Answer 361

A

40 above years old

20-200-220

Answer 362

A

Chylomicrons

Answer 363

A

ApoB = LDL, VLDL, IDL, CM

ApoA = HDL - activates LCAT
ApoC = cofactor for LPL
ApoE = ligand for LDL-R

Answer 364

A

post renal azotemia

pre-renal azotemia = BUN:CREA ratio is >20:1

Answer 365

A

1 and 2

dx sensi = positive
dx speci = negative
accuracy and precision = QA

Answer 366

A

Fixed angle

Answer 367

A

Cystatin C = Indirect GFR = BEST

BUN and CREA = direct GFR
B2 - microglobulin = tubular function

Answer 368

A

Sensitivity

Specificity = all negative

Answer 369

A

b. cirrhosis, nephrotic syndrome, MM
Reverse A:G ratio = dec albumin, inc globulin

immunodeficiency = dec globulin
cirrhosis = dec albumin
nephrotic syndrome = dec albumin, inc alpha-2 gamma glo
MM = inc gamma globulin
hypogammaglobulinemia = dec globulin

Answer 370

A

b. creatinine
creatinine – PO4 +ADP -CK> creatinine +ATP

Urea - (catabolism) protein
Uric acid (catabolism) nucleic acid

Glucose - (anabolism)
proteins and NA –gluconeogenesis (ana) > glucose

Answer 371

A

Cystatin C - marker for kidney function

Answer 372

A

c. factor assay = not all

a. bilirubin = metabolic
b. enzymes = hepatic injury and obstruction
d. prothrombin = synthetic

1st factor affected: FVII (extrinsic pathway PT)

Answer 373

A

b. bilirubin = bile acid and bile salt

a. prothrombin time = synthetic
c. albumin = synthetic
d. transaminases = injury

Answer 374

A

c. transaminases

a. prothrombin time = synthetic
b. bilirubin = metabolic, excretory, synthetic
d. albumin = synthetic

Answer 375

A

increases

Answer 376

A

C. activator = inorganic cofactor - important part in enzyme function

b. coenzyme = inorganic factor

Answer 377

A

1, 2

Catalyzes the transfer of chemical or functional group from one substance to another = TRANFERASE
Catalyzes intramolecular rearrangement of the substrate compound = ISOMERASE
Increased activity EXTRACELLULARLY when red cells are damaged (hemolysis)
INC LD
INC AST
INC CK

Answer 378

A

a. isomerase = rearrangement

b. ligase = joins with 2 ATP
c. transferase = transfer
d. oxireductase = redox

Answer 379

A

d. AST

LDH = least specific

Answer 380

A

b. acute pancreatitis

Answer 381

A

200mg/dl

400mg/dl = unacceptably large

Answer 382

A

apo-B48 = CM
apo-B100 = VLDL, LDL, IDL

HDL = apo AI and apo AII

Answer 383

A

d. A and C
For kidney function and GFR

Answer 384

A

Glucose: 160-180
Sodium: 120 mmol/L (110-130mmol/L)

Answer 385

A

c. organic mercury - animal, soil, plant; can reach BBB

a. elemental mercury = not readily absorbed
b. inorganic mercury = Hg and Hg2+

Answer 386

A

Fluid retention and low serum sodium

ADH - prevent urine formation
*SIADH - syndrome of inappropriate ADH secretion

Answer 387

A

c. renal failure

a. diuretic use - Na, K, Cl, HCO3, Mg
b. hypokalemia - water retention

Answer 388

A

b. irreversible

reversible = acute
irreversible = chronic

Answer 389

A

130 mmol/L

Answer 390

A

Serum and urine osmolality

Answer 391

A

2 and 3 - chloride shift

*should be 1, 2, 3

Answer 392

A

c. detect osmolal gap - ethanol poisoning

detect anion gap: metabolic acidosis

Answer 393

A

2 x [NA] + [Glucose] + [BUN] (mmol/L)

Answer 394

A

c. 1,2,3 (also hemolysis)

Thrombocytosis = inc clotting = inc K+
Thrombocythemia = dec K+

Answer 395

A

Osmolality

Answer 396

A

CHLORIDE!!

Answer 397

A

All of the above (A,B,C)

Answer 398

A

3, 4

severe burn = excess Na loss
CHF = H2O retention

Answer 399

A

c. hemosiderosis = minimal or no tissue damage, inc TIBC

a. sideroblastic anemia = defective heme synthesis leading to iron overload in erythroblasts (Dimorphic population of RBCs)
b. hemochromatosis = dec TIBC, there is tissue damage
d. chron’s disease = inflammatory bowel disease

Answer 400

A

a. Phosphate

Answer 401

A

b. kidneys = HCO3

lungs = CO2

pH = 6.1 + log (HCO3/H2CO3)
H2CO3 = PCO2 x 0.03

Answer 402

A

Uncompensated respiratory alkalosis
Fully compensated metabolic alkalosis

Answer 403

A

A. Glucose loading
GH = hyperglycemic hormone

Answer 404

A

a. low
Stress = starvation = dec TBG, albumin, prealbumin
Thyroxine - neo, gly, glucose absorption

Answer 405

A

a. thyroiditis

Answer 406

A

T7
TSH
TBG
rT3 (inc)
T3 uptake

Answer 407

A

d. myxedema = severe hypothyroidism (edema throughout the body)

a. hirsutism = hair growth
b. infertility = impaired ovulation
c. obesity = hormonal imbalance

Answer 408

A

d. skin - Vit. D and estrogen
* if B is a major endocrine gland, skin is secondary site of hormone production

Liver - TPO, angiotensinogen
Pancreas - glucagon, insulin, somatostatin

Answer 409

A

Secreted by the posterior pituitary gland
Synthesized by the hypothalamus

Answer 410

A

Calcitonin - tumor marker (medullary thyroid carcinoma)
Thyroglobulin (thyroid tissue)

Answer 411

A

None of the above

LH
Female = stimulates progesterone
Male = stimulates testosterone

All hormones have a specific function
LH is produced by anterior pituitary gland
Sertoli cells: produce (nourish) sperm cells

Answer 412

A

a. progesterone

Answer 413

A

Valproic acid
Ethosuximide (zarotin) - measured by immunoassays

Answer 414

A

1, 2 = bronchodilator

digoxin and procainamide - cardioactive

Answer 415

A

a. CNS depressant

Answer 416

A

methamphetamine aka designer drugs

Answer 417

A

c. methotrexate - anti-neoplastic (anti-cancer chemo drug)

a. barbiturates - anti-convulsant
b. benzodiazepines - anti-convulsant
d. cannabinoids - drug of abuse (addiction)

Answer 418

A

C. cocaine - CNS stimulant

Answer 419

A

d. Anti-depressant - TCA
Lithium - mania and depression (bipolar disorder)

Answer 420

A

d. marijuana

Answer 421

A

a. whole blood

b. hair - arsenic, keratin

Answer 422

A

B. Mercury

Answer 423

A

d. arsenic = Mee’s lines (fingernails)

Answer 424

A

Oral

Oral administration is the most common route of delivery.

Answer 425

A

Intravenous

Intravenous (IV) administration into the circulatory system offers the most direct route with effective delivery to their sites of action.

Answer 426

A

Rectal

Rectal delivery (suppository) is commonly used in infants and in situations in which oral delivery is unavailable.

Answer 427

A

Rise

Serum concentrations rise when the rate of absorption exceeds distribution and elimination.

The concentration declines as the rate of elimination and distribution exceeds absorption.

The rate of elimination can only be determined after absorption and distribution are complete.

Answer 428

A

Declines

Serum concentrations rise when the rate of absorption exceeds distribution and elimination.

The concentration declines as the rate of elimination and distribution exceeds absorption.

The rate of elimination can only be determined after absorption and distribution are complete.

Answer 429

A

Timing of specimen collection

Timing of specimen collection is the single most important factor in TDM.

In general, trough concentrations for most drugs are drawn right before the next dose; peak concentrations are drawn 1 hour after an orally administered dose.

Answer 430

A

Serum or plasma

Serum or plasma is the specimen of choice for the determination of circulating concentrations of most drugs.

Heparinized plasma is suitable for most drug analysis. The calcium-binding anticoagulants add a variety of anions and cations that may interfere with analysis or cause a drug to distribute differently between cells and plasma. As a result, ethylenediaminetetracetic acid (EDTA), citrated and oxalated plasma are not usually acceptable specimens.

Answer 431

A

Aminoglycoside

Aminoglycosides are a group of chemically related antibiotics used for the treatment of infections with gram-negative bacteria that are resistant to less toxic antibiotics.

Answer 432

A

Phenobarbital

Answer 433

A

Phenytoin

Phenytoin (Dilantin) is a commonly used treatment for seizure disorders.

Answer 434

A

Methotrexate

Answer 435

A

Xenobiotics

Answer 436

A

Greater than 2.0

Answer 437

A

Isopropyl alcohol

Answer 438

A

Decrease amount of oxygen delivered to tissue

Answer 439

A

100% oxygen therapy

Answer 440

A

Hepatotoxicity

Answer 441

A

Methylenedioxymethylamphetamine

Methylenedioxymethylamphetamine (MDMA) is an illicit amphetamine derivative that is commonly referred to as “ecstasy.”

Answer 442

A

8 to 9 hours

Half-life of ecstasy: 8 to 9 hours

Half-life of THC: 1 day after a single use and 3 to 5 days in chronic, heavy consumers

Half-life of cocaine: 0.5 to 1 hour

Half-life of benzoylecgonine: 4 to 7 hours

Answer 443

A

0.5 to 1 hour

Half-life of ecstasy: 8 to 9 hours

Half-life of THC: 1 day after a single use and 3 to 5 days in chronic, heavy consumers

Half-life of cocaine: 0.5 to 1 hour
Cocaine’s short half-life is a result of rapid hepatic hydrolysis to inactive metabolites.

Half-life of benzoylecgonine: 4 to 7 hours

Answer 444

A

Heroin

OPIATES:
The naturally occurring substances include opium, morphine, and codeine.

Heroin, hydromorphone (Dilaudid), and oxycodone (Percodan) are chemically modified forms of the naturally occurring opiates.

Meperidine (Demerol), methadone (Dolophine), propoxyphene (Darvon), pentazocine (Talwin), and fentanyl (Sublimaze) are the common synthetic opiates.

Answer 445

A

By lowering the activation energy

Enzymes accelerate reactions by lowering the activation energy needed to overcome the transition state on the way to product formation.

Answer 446

A

Hyperventilation

Answer 447

A

Hyperventilation

Answer 448

A

p02 and pH increase, pC02 decreases

Answer 449

A

4 pyrrole rings bound to an iron molecule

Answer 450

A

The total amount of iron that can be bound by transferrin

Answer 451

A

Multiple myeloma

Answer 452

A

Alpha-fetoprotein

Answer 453

A

Chylomicron

Answer 454

A

Emphysema

Answer 455

A

Red blood cell hemolysis

Answer 456

A

Serum lipase

Answer 457

A

Cholesterol

Answer 458

A

Hirsutism

Answer 459

A

Myasthenia gravis

Answer 460

A

Peripheral neuropathy

Answer 461

A

Very low or absent HDL

Answer 462

A

Tacrolimus

Tacrolimus (proprietary name: Prograf) is used to prevent rejection of heart, allogenic liver and kidney transplants.

Answer 463

A

Theophyliine

Theophylline (proprietary name: Theo-Dur) is used to treat moderate or severe asthma.

Answer 464

A

Diazepam

Diazepam (proprietary name: Valium) is in a class of drugs called benzodiazepines, which are sedative-hypnotics.

Answer 465

A

It is associated with an insufficient amount of insulin secreted by the pancreas

Answer 466

A

Can develop type 2 diabetes at a later date

Answer 467

A

The serum should be observed for hemolysis; hemolysis of the red cells will shift potassium from the cells into the serum, resulting in a falsely elevated potassium value

Answer 468

A

Test in the electrolyte profile (sodium, potassium, chloride and bicarbonate)

Answer 469

A

Bicarbonate ions

Answer 470

A

Very low; renal glomerular filtration is not functioning normally

Late stages of renal failure show increased serum potassium
and phosphorus and decreased serum calcium and urinary potassium.

Creatinine clearance decreases, often to less than 50 mL/min compared with reference ranges.

Answer 471

A

21 mg/dL

10 mg/dL x 2.14 = 21.4 mg/dL

Answer 472

A

Increased creatinine

Answer 473

A

Triglycerides

Serum or plasma specimens collected from patients in blood collection tubes who have fasted for at least 12 hours are required for triglyceride testing.

Answer 474

A

HDL cholesterol < 35 mg/dL

Answer 475

A

The cholesterol is normal, but the triglyceride test is elevated; retest using a 12-hour fasting specimen, because the triglyceride test is affected by the recent meal

Answer 476

A

Hemolytic anemia in which his red blood cells are being destroyed

Answer 477

A

Potassium

As the primary intracellular cation, potassium is an integral part of the transmission of nerve impulses. Movement of potassium across the nerve tissue membrane permits the neural signal to move down the nerve fiber. Potassium also seems to be involved in synaptic processes, where the impulse “jumps” from one nerve fiber to another.

Answer 478

A

Bicarbonate

Bicarbonate is the second most abundant anion in the extracellular fluid. It is a major component of the blood buffering system, accounts for 90% of total blood carbon dioxide, and maintains charge neutrality in the cell.

Answer 479

A

Gluconeogenesis

Gluconeogenesis is the formation of glucose from amino acids and lipids that occurs when carbohydrate intake decreases.

Glycogenesis is the process of glycogen formation by enzyme action on glucose to eventually form glycogen.

Glycogenolysis is the breakdown of glycogen, with the eventual formation of glucose-6-phosphate or free glucose that can be used for energy production.

Glycolysis is the catabolism of glucose to pyruvate or lactate for adenosine triphosphate (ATP) production (Embden-Meyerhof pathway and Krebs’ cycle).

Answer 480

A

Lucey-Driscoll syndrome

Lucey–Driscoll syndrome is a rare form of jaundice caused by unconjugated bilirubin that presents within 2–4 days of birth and can last several weeks. It is caused by an inhibitor of UDP-glucuronyl transferase in maternal plasma that crosses the placenta. Jaundice is usually severe enough to require treatment.

Answer 481

A

Increased

INCREASED ANION GAP
1. Uremia/renal failure, which leads to PO4- and SO42- retention
2. Ketoacidosis, as seen in cases of starvation or diabetes
3. Methanol, ethanol, ethylene glycol poisoning, or salicylate
4. Lactic acidosis
5. Hypernatremia
6. Instrument error

DECREASED ANION GAP
1. Hypoalbuminemia (decrease in unmeasured anions)
2. Severe hypercalcemia (increase in unmeasured cations)

Answer 482

A

Viral hepatitis

Answer 483

A

4 to 6 hours

Answer 484

A

Decreased, increased, increased

Answer 485

A

Normal T3 T4, increased TSH

In subclinical hypothyroidism, the TSH is minimally increased while the free T4 stays within the normal range.

Likewise, in subclinical hyperthyroidism, the TSH is suppressed while the free T4 is normal.

Brainscape's Knowledge GenomeTM

CC Flashcards

Brainscape's Knowledge Genome^TM