CC EXAMS Flashcards
The measurement of voltage between two electrodes in a solution forms the basis for a variety of procedures for measuring analyte concentration:
Potentiometry
It is based on fragmentation and ionization of molecules using a suitable source of energy:
Mass spectrometry
Generally it is used to detect gamma radiation:*
Crystal scintillation counter
A technique for determining the structure of organic compounds; it is nondestructive, although it does require a larger sample volume:
Nuclear magnetic resonanance
Low anion gaps:
Hypoalbuminemia, hypercalcemia and multiple myeloma
The main waste product of nitrogen-containing chemicals in the body:
Urea
The combination of a weak acid or weak base and its salt, is a system that resists changes in pH:
Buffer
The role of the lungs and kidneys in maintaining pH is depicted with the Henderson-Hasselbalch equation. The numerator denotes:
Kidney function
The role of the lungs and kidneys in maintaining pH is depicted with the Henderson-Hasselbalch equation. The denominator denotes:
Lung function
The fifth most common element and is the most prevalent cation in the human body:
Calcium
The fourth most abundant cation in the body and the second most prevalent intracellular cation:
Magnesium
An abnormal lipoprotein found in patients with obstructive biliary disease and in patients with familial lecithin/cholesterol acyltransferase (LCAT) deficiency:
LpX lipoprotein
Lipoprotein(s) have a density of less than 1.006 kg/L (density measurement):
Chylomicrons and VLDL
A striking elevation of transferrin in the β-region sometimes occurs in patients suffering from:
Iron deficiency anemia: A striking elevation of transferrin in the β-region sometimes occurs in patients suffering from iron deficiency anemia. The increase in transferrin corresponds to increased IBC, and the percent saturation is low.
Enzymes _____ the activation energies of the chemical reactions that they catalyze, so as to cause greatly enhanced rates of reaction.
Lower
Different forms of enzymes that catalyze the same reaction:
Isoenzymes
This probably represents alcohol dehydrogenase:
LD6
Stated as E + S = ES = E + P*
Catalytic mechanism
Panic reactions—a bad trip—are the most common adverse reactions.
Lysergic acid diethylamide
The drug of choice for absence (petit mal) seizures unaccompanied by other types of seizures:
Ethosuximide (Zarontin)
Anti-asthmatic drugs:
Theophylline and theobromine: 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.
An indication of error in the analysis, detected by a progressive drift of control values in one direction for at least 5 consecutive runs:
Trend
The most common drug of abuse and is frequently responsible for the presentation of patients with altered mental status to hospitals and emergency rooms:
Ethanol
Centrifuge used when rapid centrifugation of solutions containing small particles is needed:
Fixed-angle centrifuge
Tests that are very simple or pose no reasonable risk of harm to the patient if the test is performed incorrectly:
Waived
It measures light blocked as a decrease in the light transmitted through the solution; dependent on particle size and concentration:
Turbidimetry
Complex tests that require skill to perform and interpret and are therefore regulated:
Nonwaived
Small particles scattering light in all directions with maximum scatter forward and backward:
Raleigh scatter
Large particles scattering light predominantly a in the forward direction:*
Mie scatter
Hemolysis is graded based on visible presence of hemoglobin, when greater than _____ mg/dL.
20 mg/dL
Pipettes used for delivering small volumes of viscous solutions such as protein or whole blood standards:
Ostwald-Folin transfer pipettes
Pipettes have a cylindrical glass bulb near the center of the pipette that helps to distinguish them from other types of transfer pipettes:
Volumetric transfer pipettes
A very high-torque and low-inertia motor to spread monolayers of cells rapidly across a special slide for critical morphologic studies:
Cytocentrifuge
Using standard serum protein electrophoresis (SPE) methods, serum proteins appear in ____ bands.
Five bands
Which of the following is not quantified in the triple test for Down syndrome?
“Progesterone:SCREENING FOR BIRTH DEFECTS
1. Triple test: AFP, HCG and ESTRIOL
2. Quadruple (QUAD) screen: AFP, HCG, ESTRIOL and INHIBIN-A”
Which of the following is not a type of support media used for serum protein electrophoresis?
Celite
What dye may be used for staining protein bands following electrophoresis?
Ponceau S
All but one protein are components of the BETA-GLOBULINS
Ceruloplasmin
The physician is concerned that a pregnant patient may be at risk for delivering prematurely. What would be the best biochemical marker to measure to assess the situation?
Fetal fibronectin
All antigen diffuse from the well and the concentration of the antigen is related to the square of the diameter of the precipitin ring:
Mancini or the endpoint RID
It requires that all rings be measured at a fixed time of 18 hours; diameter of the precipitin ring is plotted against the antigen concentration on a logarithmic scale:
Fahey-McKelvey or the kinetic RID
Direct measurements of T4, except:
Uptake
Of the total serum osmolality, sodium, chloride, and bicarbonate ions normally contribute approximately what percent?
92%
Hepatic cirrhosis:
Hyponatremia due to increased water retention
Diabetes insipidus:
Hypernatremia due to excess water loss
Increased antidiuretic hormone:
Fluid retention, low serum sodium
Decreased anion gaps of less than 10 mmol/L
Increased unmeasured cations or decreased unmeasured anions
For each degree of fever in the patient, pO2 will ____ and pCO2 will ______.
pO2 will fall 7% and pCO2 will rise 3%
What is the predominant form of thyroid hormone in the circulation?
Thyroxine
Patient has signs and symptoms suggestive of acromegaly. The diagnosis would be confirmed if the patient had which of the following?
No decrease in serum growth hormone concentration 90 minutes after oral glucose administration
The target DNA must be denatured to ____ before it can serve as a template for the PCR reaction.
Single-stranded DNA
An isotonic saline solution contains 0.85% NaCl. How many grams of NaCl are needed to prepare 5 L of this solution?
42.5 grams
Excess CSF should be:
*
Frozen
Convert 50 mL to L
0.05
50 mL (milli = 10^-3 and is smaller) = ? L (larger by 10^3); move the decimal by three places to the left and it becomes 0.050 L.
Which of the following containers is calibrated to hold only one exact volume of liquid?
Volumetric flask
A Class A volumetric flask is calibrated to hold one exact volume of liquid (TC).
Which of the following standards requires that SDSs are accessible to all employees who come in contact with a hazardous compound?
Hazard Communication Standard
In the August 1987 issue of the Federal Register, OSHA published the new Hazard Communication Standard (Right to Know Law, 29 CFR 1910.1200).
Which of the following is the proper means of disposal for the type of waste?
Microbiologic waste by steam sterilization
Which of the following are examples of NONIONIZING RADIATION?
Ultraviolet light and microwaves
10 6th
Mega
Concentration expressed as the amount of solute per 100 parts of solution:
Percent solution
Indication of relative concentration:
Dilution
What is the molarity of a solution that contains 18.7 grams of KCl in 500 mL (MW 74.5)?
M = 18.7 g / (74.5)(0.5L) = 0.5 M
How much 95% v/v alcohol is required to prepare 5L of 70% v/v alcohol?
3.7 L
C1V1 = C2V2
V1 = (70)(5L) / 95 = 3.7 L
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 100
Amount of serum: 0.1 mL
Total volume: 10 mL
Dilution: 0.1:10 or 1:100
Convert 72 Fahrenheit to its Celsius equivalent:
C = 5/9 (F - 32)
= 5/9 (72 - 32)
= 22.2C
Most basic pipette:
Glass pipette
ROUTINELY USED: automatic pipette
MOST BASIC: glass pipette
Does not have graduations to the tip:
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.
Pipets are used with biologic fluids having a viscosity greater than that of water:
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.
Pipette with BULB CLOSER TO THE DELIVERY TIP and are used for accurate measurement of VISCOUS FLUIDS, such as blood or serum:
Ostwald-Folin pipette
Pipette with cylindrical glass bulb near the CENTER of the pipette that helps to distinguish them from other types of transfer pipettes.
Volumetric pipette
Extremely inert, excellent temperature tolerance and chemical resistance; used for stir bars, stopcocks and tubing:
Teflon
It is used when rapid centrifugation of solutions containing small particles is needed; an example is the microhematocrit centrifuge:
Fixed-angle head centrifuge
High-speed centrifuges used to separate layers of different specific gravities, commonly used to separate lipoproteins:
Ultracentrifuge
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
Uses a very high-torque and low-inertia motor to spread MONOLAYER OF CELLS rapidly across a special slide for critical morphologic studies:
Cytocentrifuge
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
Calibration of centrifuges is customarily performed every ______.
*
Every 3 months (quarterly)
centrifuges are routinely disinfected on a ___ basis.
Weekly
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
The PUREST TYPE OF REAGENT WATER is:
Type I
Chemicals that are used to manufacture drugs:
USP and NF chemical grade
Which of the following is NOT A COLLIGATIVE PROPERTY of solutions?
pH
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
Degree of hazard #2:
Moderate
DEGREE OF HAZARD
0: NO OR MINIMAL
1: SLIGHT
2: MODERATE
3: SERIOUS
4: EXTREME
All of the following are CRYOGENIC MATERIALS HAZARDS, EXCEPT:
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.
When a person is receiving an electrical shock, all of the following should be done EXCEPT:
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.
Most common source of light for work in the visible and near-infrared regions:
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.
The lamps most commonly used for ultraviolet (UV) work are:
Deuterium discharge lamp and mercury arc lamp
Which is the most sensitive detector for spectrophotometry?
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.
Reflectance spectrometry uses which of the following?
Tungsten–halogen lamp
Slide technology depends on reflectance spectrophotometry.
For colorimetric determinations, the light source is a tungsten–halogen lamp.
Which of the following light sources is used in atomic absorption spectrophotometry?
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.
Used to measure concentration of LARGE PARTICLES: 1. Nephelometry 2. Turbidimetry 3. Absorption spectroscopy
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.
Which of the following techniques measures light scattered and has a light source placed at 90 degrees from the incident light?
Nephelometry
Which of the following instruments is used in the clinical laboratories to detect beta and gamma emissions?
Scintillation counter
Which of the following types of analyzers offers RANDOM-ACCESS CAPABILITIES?
Discrete analyzers
Checking instrument calibration, temperature accuracy, and electronic parameters are part of:
Function verification
Function verification includes monitoring temperature, setting electronic parameters, calibrating instruments and analyzing control data.
A pre-analytical error can be introduced by:
Vigorously shaking the blood tube to prevent clotting
Vigorously mixing can cause hemolysis.
The following data were calculated on a series of 30 determinations of serum uric acid control: mean = 5.8 mg/dL, 1 standard deviation = 0.15 mg/dL. If confidence limits are set at ± 2 SD, which o f the following represents allowable limits for the control?
5.50 to 6.10 mg/dL
Standard deviation is a measure of the dispersion of data around the mean.
Systematic errors include: PLEASE CHECK 3 BOXES.
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
Random errors include: PLEASE CHECK 3 BOXES.
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
Most frequently occurring value in a dataset:
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.
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 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.
Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration.
Proportional error:
Type of systemic error where the magnitude changes as a percent of the analyte present; error dependent on analyte concentration.
Difference between the observed mean and the reference mean:
Bias:
Difference between the observed mean and the reference mean.
The term R:4S means that:
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).
Which of the following terms refers to deviation from the true value caused by indeterminate errors inherent in every laboratory measurement?
Random error
Random errors are deviations from the true value caused by unavoidable errors inherent in laboratory measurements.
A trend in QC results is most likely caused by:
Deterioration of the reagent
MAIN CAUSE OF TREND: DETERIORATION OF REAGENTS
A trend occurs when six or more consecutive quality control results either increase or decrease in the same direction; however, this is not cause for rejection until a multirule is broken. Trends are systematic errors (affecting accuracy) linked to an unstable reagent, calibrator, or instrument condition.
Which of the following plots is best for detecting all types of QC errors?
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.
Which of the following plots is best for comparison of precision and accuracy among laboratories?
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.
Which plot will give the earliest indication of a shift or trend?
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.
Which of the following terms refers to the closeness with which the measured value agrees with the true value?
Accuracy
Which of the following describes the ability of an analytical method to maintain both accuracy and precision over an extended period of time?
Reliability
In a person with normal glucose metabolism, the blood glucose level usually increases rapidly after carbohydrates are ingested but returns to a normal level after:
120 minutes (2 hours)
Glucose measurements can be ____ mg/dL erroneously higher by reducing methods than by more accurate enzymatic methods.
5 to 15 mg/dL
Select the enzyme that is most specific for beta D-glucose:
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.
Select the coupling enzyme used in the hexokinase method for glucose:
Glucose-6-phosphate dehydrogenase
Gross hemolysis and extremely elevated bilirubin may cause ______ in HEXOKINASE RESULTS.
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.
Resting plasma glucose
NORMAL <140
IMPAIRED 140 – 199
DIAGNOSTIC ≥ 200 mg/dL
Fasting plasma glucose
NORMAL <100
IMPAIRED 100 – 125
DIAGNOSTIC ≥ 126 mg/dL
What is the recommended cutoff value for adequate control of blood glucose in diabetics as measured by glycated hemoglobin?
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.
2-hour OGTT
NORMAL <140
IMPAIRED 140 – 199
DIAGNOSTIC ≥ 200 mg/dL
HbA1c
NORMAL <5.7 %
IMPAIRED 5.7 – 6.4%
DIAGNOSTIC ≥ 6.5%
Which test is the most sensitive in detecting early monoclonal gammopathies?
Serum-free light chain immunoassay
Measurement of free light chains is recommended along with protein electrophoresis when testing for myeloma.
Free light chains are normally present in serum because L chains are made at a faster rate than H chains.
Patients with Waldenström’s macroglobulinemia exhibit abnormally large amounts of:
IgM
Waldenström’s primary macroglobulinemia (WM), or simply macroglobulinemia, is a B cell disorder characterized by the infiltration of lymphoplasmacytic cells into bone marrow and the presence of an IgM monoclonal gammopathy.
Which test is the most useful way to evaluate the response to treatment for multiple myeloma?
Measurement of serum-free light chains
Unlike electrophoresis methods, serum free light chain assays are quantitative and an increase in free light chain production with an abnormal kappa:lambda ratio occurs earliest in recurrence of myeloma.
A sensitive, although not specific indicator of damage to the kidneys:
Proteinuria
At pH 8.6, proteins are _________ charged and migrate toward the _________.
Negatively, anode
For albumin assay, absorbance at 630 nm is less likely to be affected by bilirubin or hemoglobin in the sample. Which dye gives a much greater absorbance change at 630 nm than it would at 500 nm?
BCG (Bromcresol green)
Precursor of the adrenal hormones epinephrine, norepinephrine, and dopamine and the thyroid hormones, including thyroxine:
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.
Nutritional assessment with poor protein-caloric status is associated with:
A decreased level of prealbumin
Which of the following is a low-weight protein that is found on the cell surfaces of nucleated cells?
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.
A glycoprotein used to help predict the short-term risk of PREMATURE DELIVERY:
Fetal fibronectin
Fetal fibronectin (fFN) is a glycoprotein used to help predict the short-term risk of premature delivery.
BIOCHEMICAL MARKER OF BONE RESORPTION that can be detected in serum and urine:
Crosslinked C-telopeptides (CTX)
An accurate marker of CSF leakage:
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.
Recently proposed new marker for the early assessment of changes to the glomerular filtration rate:
Cystatin C
Supplemental tests to help differentiate a diagnosis of ALZHEIMER DISEASE from other forms of dementia:
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.
Which two tests detect swelling of the ventricles that occurs in congestive heart failure?
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.
Which test, if elevated, would PROVIDE INFORMATION about risk for developing coronary artery disease?
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
If elevated, which laboratory test would support a diagnosis of CONGESTIVE HEART FAILURE?
B-type natriuretic peptide
Which of the following laboratory tests is a marker for ISCHEMIC HEART DISEASE?
Albumin cobalt binding
Albumin cobalt binding is a test that measures ischemia-modified albumin, which is a marker for ischemic heart disease.
The turbid, or milky, appearance of serum after fat ingestion is termed postprandial lipemia, which is caused by the presence of what substance?
Chylomicron
The kinetic methods for quantifying serum triglyceride employ enzymatic hydrolysis. The hydrolysis of triglyceride may be accomplished by what enzyme?
Lipase
When the plasma appears OPAQUE AND MILKY, 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
The largest and the least dense of the lipoprotein particles:
Chylomicrons
A commonly used precipitating reagent to separate HDL cholesterol from other lipoprotein cholesterol fractions:
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.
The smallest and most dense lipoprotein particle:
HDL
Sinking pre-β-lipoprotein:
Lp(a)
A patient’s total cholesterol is 300 mg/dL, his HDL cholesterol is 50 mg/dL, and his triglyceride is 200 mg/dL. What is this patient’s calculated LDL cholesterol?
210
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
Floating beta lipoprotein:
B-VLDL
Select the order of mobility of lipoproteins electrophoresed on cellulose acetate or agarose at pH 8.6.
– Chylomicrons →β→pre-β→α +
In the urea method, the enzymatic action of urease is inhibited when blood for analysis is drawn in a tube containing what anticoagulant?
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.
In the diacetyl method, what does diacetyl react with to form a yellow product?
UREA
In the diacetyl method, acidic diacetyl reacts directly with urea to form a yellow-diazine derivative.
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 _____.
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%.
When mixed with phosphotungstic acid, what compound causes the reduction of the former to a tungsten blue complex?
Uric acid
Which of the following disorders is best characterized by laboratory findings that include increased serum levels of inorganic phosphorus, magnesium, potassium, uric acid, urea, and creatinine and decreased serum calcium and erythropoietin levels?
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.
A complete deficiency of hypoxanthine guanine phosphoribosyl transferase results in which disease?
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.
During chemotherapy for leukemia, which of the following analytes would most likely be elevated in the blood?
Uric acid
What is the IMMEDIATE PRECURSOR of bilirubin formation?
Biliverdin
It is biliverdin that is the immediate precursor of bilirubin formation. Mesobilirubinogen and urobilinogen represent intestinal breakdown products of bilirubin catabolism.
To quantify serum bilirubin levels, it is necessary that bilirubin couples with diazotized sulfanilic acid to form what complex?
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.
In the condition kernicterus, the abnormal accumulation of bilirubin occurs in what tissue?
Brain
Which of the following factors will NOT adversely affect the accurate quantification of bilirubin in serum?
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.
Which bilirubin fraction is conjugated and covalently bound to albumin? Bishop
Delta
Four bilirubin fractions represented by Greek letters have been identified: unconjugated (alpha), monoconjugated (beta), diconjugated (gamma), and unconjugated bilirubin covalently bound to albumin (delta).
As the red blood cells disintegrate, hemoglobin is released and converted to the pigment bilirubin. Which organ is primarily responsible for this function?
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.
Which of the following does NOT accurately describe direct bilirubin?
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.
Which of the following reagent systems contains the components sulfanilic acid, hydrochloric acid, and sodium nitrite?
Diazo
Ehrlich’s DIAZO REAGENT consists of sulfanilic acid, hydrochloric acid, and sodium nitrite.
Which of the following disorders is characterized by an INABILITY TO TRANSPORT BILIRUBIN from the sinusoidal membrane into the hepatocyte?
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.
Indirect-reacting bilirubin may be quantified by reacting it initially in which reagent?
Caffeine-sodium benzoate
EVELYN-MALLOY: methanol
JENDRASSIK-GROF: caffeine-sodium benzoate
Which of the following is NOT characteristic of Dubin-Johnson syndrome?
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.
Beta-gamma bridging effect:
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
When measuring enzyme activity, if the instrument is operating 5°C lower than the temperature prescribed for the method, how will the results be affected?
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.
Increased in hepatic jaundice:
B1 and B2
Hemolytic jaundice: unconjugated bilirubin (B1)
Hepatic jaundice: unconjugated and conjugated bilirubin (B1 and B2)
Obstructive jaundice: conjugated bilirubin (B2)
The properties of enzymes are correctly described by which of the following statements?
Enzymes are protein catalysts of biological origin.
The shape of the key (substrate) must fit into the lock (enzyme):
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
The reaction rate is directly proportional to substrate concentration:
First-order kinetics
The reaction is following first-order kinetics because the reaction rate is directly proportional to substrate concentration.
An organic cofactor, such as nicotinamide adenine dinucleotide (NAD):
*
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.
The reaction rate depends only on enzyme concentration:
Zero-order kinetics
The reaction is following first-order kinetics because the reaction rate is directly proportional to substrate concentration.
Inorganic cofactors, such as chloride or magnesium ions:
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).
The smallest enzyme:
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.
To what class of enzymes does lactate dehydrogenase belong?
Oxidoreductases
Catalyze the joining of two substrate molecules, coupled with breaking of the pyrophosphate bond in adenosine triphosphate (ATP) or a similar compound:
Ligases
Catalyze removal of groups from substrates without hydrolysis; the product contains double bonds
Lyases
Catalyze hydrolysis of various bonds
Hydrolases
Catalyze the interconversion of geometric, optical, or positional isomers
Isomerases
Enzymes catalyze physiologic reactions by ____ the activation energy level that the reactants (substrates) must reach for the reaction to occur.
Decreasing the activation energy
To aid in the diagnosis of skeletal muscle disease, which of the following serum enzyme measurements would be of most use?
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.
Which of the following disorders is NOT associated with an elevation of serum creatine kinase?
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.
Pathological levels are DECREASED from the normal values, sometimes as much as 80 to 90%:
Cholinesterase
Normal serum levels of cholinesterase are quite high, reflecting its continual synthesis and release by the liver. Decreased values are considered abnormal.
All of the following are macroenzymes, except:
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).
Which of the following buffers is used in the IFCC recommended method for ALP?
2-Amino-2-methyl-1-propanol
The method of Bowers–McComb (Szasz modification) is the IFCC-recommended method for ALP. This method uses 2-amino-2-methyl-1-propanol, pH 10.15, and measures the increase in absorbance at 405 nm as p-nitrophenyl phosphate is hydrolyzed to p-nitrophenol.
Kinetic enzymatic assays are best performed during which phase of an enzymatic reaction?
Linear phase
Enzyme assays are recommended to be performed during the linear phase, so that a consistent change over time can be used to calculate the enzyme concentration.
To what metal does ceruloplasmin firmly bind?
Copper
Copper is found in the plasma mainly in two forms: a minor fraction loosely bound to albumin and the majority, representing about 80-95%, firmly bound to the enzyme ceruloplasmin, an alpha2-globulin, which is important in the oxidation of iron from the ferrous to the ferric state.
Which trace metal is contained in glucose tolerance factor?
Chromium
Manganese toxicity resembles the following disease:
Parkinson’s disease
Chronic manganese toxicity resembles Parkinson’s disease with akinesia, rigidity, tremors, and mask-like faces.
Direct effectors:
- GH
- Prolactin
Tropic hormones:
- ACTH
- FSH
- LH
- TSH
The metal ion essential for the activity of xanthine oxidase and xanthine dehydrogenase is:
Molybdenum
Molybdenum is vital to human health through its inclusion in at least three enzymes: xanthine oxidase, aldehyde oxidase, and sulfite oxidase. The active site of these enzymes binds molybdenum in the form of a cofactor “molybdopterin”.
Neurohypophysis
Posterior pituitary gland
Adenohypophysis:
Anterior pituitary gland
Prolactin is produced by the
Anterior pituitary gland
Also called somatotropin
GH
Growth hormone (GH), also called somatotropin, is structurally related to prolactin and human placental lactogen.
A patient has an elevated serum T3 and free T4 and undetectable TSH. What is the most likely cause of these results?
Primary hyperthyroidism
The definitive suppression test to prove autonomous production of growth hormone is:
Oral glucose loading
Which test is used to distinguish Cushing’s disease (pituitary Cushing’s) from Cushing’s syndrome caused by adrenal tumors?
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
The serum TSH level is almost absent in:
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
Select the most appropriate single screening test for thyroid disease.
TSH assay
Critical for sodium retention (volume), potassium, and acid–base homeostasis.
Aldosterone
Which of the following is the mechanism causing Cushing’s disease?
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.
Which is the most widely used screening test for Cushing’s syndrome?
Overnight low-dose dexamethasone suppression test
The parent substance in the biosynthesis of androgens and estrogens is:
Cholesterol
Select the main estrogen produced by the ovaries and used to evaluate ovarian function.
Estradiol (E2 )
The biologically most active, naturally occurring androgen is:
Testosterone
Zollinger–Ellison (Z–E) syndrome is characterized by great (e.g., 20-fold) elevation of:
Gastrin
Levels of 8-9% carboxyhemoglobin saturation of whole blood are commonly found in which of the following situations?
Cigarette smokers
Cigarette smokers exhibit levels of 8-9% carboxyhemoglobin, but occasionally saturations of greater than 16% have been reported in heavy smokers.
Heroin is synthesized from what drug?
Morphine
Heroin (diacetylmorphine), an abused drug, is a derivative of morphine. The morphine used in its synthesis is generally obtained from opium.
This toxin has high affinity to keratin, can be identified from hair and nails:
Arsenic
Identification of the urinary metabolite benzoylecgonine would be useful in determining exposure to which of the following drugs?
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.
THC (tetrahydrocannabinol) is the principal active component of what drug?
Marijuana
THC (tetrahydrocannabinol) is the principal active component of marijuana.
CNS DEPRESSANTS
Barbiturates;
methaqualone;
benzodiazepines including Valium; and oxycodone and other opiates,
morphine, heroin (which metabolizes to morphine), codeine (methylmorphine), and methadone
Which substance has the longest detection time?
Marijuana
Marijuana is stored in fatty tissue and is metabolized slowly.
HALLUCINOGENS OR PSYCHOACTIVES
Cannabinoids and phencyclidine (PCP)
Methylenedioxymethylamphetamine (MDMA) is an illicit amphetamine derivative that is commonly referred to as:
Ecstacy
All of the following are CNS depressant, EXCEPT:
Cocaine
CNS STIMULANTS
Cocaine and its metabolite, benzoylecgonine, and amphetamines and methamphetamines
ANTIDEPRESSANTS
Lithium, tricyclic antidepressants
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:
Cyanide overdose
Increased trough levels of aminoglycosides in the serum are often associated with toxic effects to which organ?
Kidney
Tobramycin and gentamicin are examples of aminoglycoside antibiotics. Their use has been associated with both nephrotoxicity and ototoxicity.
The ODOR OF GARLIC may be on the breath, and a METALLIC TASTE in the patient’s mouth:
Arsenic toxicity
Which of the following drugs is used as an immunosuppressant in organ transplantation, especially in liver transplants?
Tacrolimus
Tacrolimus (Prograf) is an antibiotic that functions as an immunosuppressant in organ transplantation, especially in liver transplants.
When is a blood sample for determination of the trough level of a drug appropriately drawn?
Shortly before drug administration
Acetaminophen is particularly toxic to what organ?
Liver
Which of the following drugs is used as a bronchodilator?
Theophylline
Bronchodilators:
1.Digoxin
2.Phencyclidine
3.Theophylline
4.Theobromine
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.
Which of the following is a commonly encountered xanthine that could potentially interfere with the determination of theophylline?
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.
Which of the following is used in the treatment of manic depression?
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.
The major toxicities of _______ are red man syndrome, nephrotoxicity, and ototoxicity.
Vancomycin
The major toxicities of vancomycin are red man syndrome, nephrotoxicity, and ototoxicity.
The drug of choice for absence (petit mal) seizures unaccompanied by other types of seizures:
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.
Which of the following do not require TDM?
1.Salicylates
2.Acetaminophen
3.Ibuprofen
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.
Which tumor marker is associated with cancer of the urinary bladder?
Nuclear matrix protein
Major cation, or positively charged particle, and is found in the highest concentration in extracellular fluid:
Sodium
It is the major anion that counterbalances the major cation, sodium.
Chloride
Major intracellular cation:
Potassium
Two main functions in the body: (1) determining the osmotic pressure, which controls the distribution of water among cells, plasma, and interstitial fluid, and (2) maintaining electrical neutrality.
Chloride
Second most abundant anion in the extracellular fluid; major component of the blood buffering system, accounts for 90% of total blood carbon dioxide, and maintains charge neutrality in the cell:
Bicarbonate
Fourth most abundant cation in the body and second most abundant intracellular ion:
Magnesium
Electrolyte(s) essential for blood coagulation:
Calcium and magnesium
Can occur when sodium is measured using indirect ion-selective electrodes (ISEs) in a patient who is HYPERPROTEINEMIC or HYPERLIPIDEMIC.
Pseudohyponatremia
The measurement of __________ is necessary to evaluate the cause of hypernatremia.
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
With increased water loss, burn patients are most likely to also experience:
Hypernatremia
Any condition that increases water loss, such as fever, burns, diarrhea, or exposure to heat, will increase the likelihood of developing hypernatremia.
Electrolyte(s) essential for acid-base balance:
Bicarbonate, potassium and chloride
Hyponatremia can also be classified according to:
Plasma/serum osmolality
Major intracellular cation in the body:
Potassium
Cellular Shift
Acidosis
Muscle/cellular injury
Chemotherapy
Leukemia
Hemolysis
Major extracellular anion:
Chloride
The second most abundant anion in the ECF:
Bicarbonate
All are associated with hyperkalemia, except:
Alkalosis
CAUSES OF HYPERKALEMIA
1. Decreased Renal Excretion
Acute or chronic renal failure (GFR < 20 mL/min)
Hypoaldosteronism
Addison’s disease
Diuretics
Most frequently observed in hospitalized individuals in intensive care units (ICUs) or those receiving diuretic therapy or digitalis therapy:
Hypomagnesemia:
Hypomagnesemia is most frequently observed in hospitalized individuals in intensive care units (ICUs) or those receiving diuretic therapy or digitalis therapy.
Of the total serum calcium, free ionized calcium normally represents approximately what percent?
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%).
Which of the following reagents is used in a colorimetric method to quantify the concentration of serum calcium?
Cresolphthalein complexone
Total serum calcium concentration is often determined by the spectrophotometric quantification of the color complex formed with cresolphthalein complexone.
Elevated anion gap
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.
Which of the following reagents is used to determine the concentration of serum inorganic phosphate?
Ammonium molybdate
Low anion gap.
Hypercalcemia
Hypoalbuminemia
Which formula is most accurate in predicting plasma osmolality?
2(Na) + (glucose ÷ 18) + (BUN ÷ 2.8)
The sample of choice for measuring blood osmolality is:
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.
Driving force of the bicarbonate buffer system:
Carbon dioxide
The following conditions are all causes of alkalosis. Which condition is associated with respiratory alkalosis?
Anxiety
A patient’s blood gas results are: pH = 7.50; pCO2 = 55 mm Hg; and HCO3– = 40 mmol/L. These results indicate:
Metabolic alkalosis
The role of the lungs and kidneys in maintaining pH is depicted with the Henderson-Hasselbalch equation. The denominator denotes:
Lung function
Osmometry is a technique for measuring the concentration of solute particles that contribute to the osmotic pressure of a solution. The most common method used in a clinical laboratory to measure osmolality is:
Freezing point depression
Osmolality is best measured using freezing point depression.
Osmolality can be measured by dew point, boiling point, osmotic pressure and freezing point however, freezing point is the most common method used in clinical laboratories.
The term used to describe reproducibility is:
Precision
Gloves worn in the laboratory for specimen processing must be removed and hands washed when:
Answering the telephone in a designated “clean” area
A laboratory employee identifies arm and neck pain after performing repetitive movements during his/her work assignment. What is the best first action to be taken?
Report to and discuss issue with supervisor
Which of the following hormones involved in calcium regulation acts by increasing the amount of calcium in the blood by enhancing absorption through the intestines, stimulation of osteoclasts, and suppressing loss in the urine?
PTH
Which of the following is true regarding indirect bilirubin?
It requires an accelerator to react with the diazo reagent
A decrease in serum haptoglobin accompanies which of the following?
Intravascular hemolysis
Which of the following electrolytes is the chief plasma cation whose main function is maintaining osmotic pressure?
Sodium
Select the test which evaluates renal tubular function.
Osmolality
The best tests for renal tubular function when investigating diabetes insipidus are serum and urine osmolality.
Which statement about TSH and T4 in early pregnancy is correct?
Estrogens released in pregnancy cause an increase in TBG, which causes an increase in total T4 and T3.
In early pregnancy, the hCG produced by the placenta stimulates the thyroid, causing an increase in free thyroid hormones. This suppresses TSH production.
Which enzyme deficiency is most commonly associated with familial hypertriglyceridemia associated with fasting plasma cholomicrons (formerly type I hyperlipoproteinemia)?
Post–heparin-activated lipoprotein lipase deficiency
Which test is the most sensitive in detecting early monoclonal gammopathies?
Serum-free light chain immunoassay
Which of the following abnormal laboratory results is found in von Gierke’s disease?
Hyperlipidemia
Which formula is most accurate in predicting plasma osmolality?
2(Na) + (glucose ÷ 18) + (BUN ÷ 2.8)
Which monochromator specification is required in order to measure the true absorbance of a compound having a natural absorption bandwidth of 30 nm?
5-nm bandpass
The most important application of IEP of urine is:
Demonstration of Bence Jones (BJ) protein
Which of the following is the most common application of immunoelectrophoresis (IEP)?
Diagnosis of monoclonal gammopathies
Which of the following is the most common application of immunoelectrophoresis (IEP)?
Diagnosis of monoclonal gammopathies
Concentration is
The amount of one substance relative to the amounts of other substances in the solution
A ratio is:
Expression of one amount relative to another amount
Dilution is:
*
Relative concentrations of the components of a mixture
Checking instrument calibration, temperature accuracy, and electronic parameters are part of
Function verification
To calibrate the pH electrode in a pH/ blood gas analyzer, it is necessary that:
Two buffer solutions of known pH be used
In spectrophotometric analysis, what is the purpose of the reagent blank?
Correct for color contribution of the reagents
Chain-of-custody procedures must be followed for:
Blood specimens for alcohol level determination
A laboratory procedure manual should be available to personnel at the workbench and must include the following elements:
Step-by-step performance instructions, reference intervals, reagent storage location, specimen collection requirements
The typical specimen collected for forensic toxicity of drugs of abuse is:
Random urine
An antiepileptic (or anticonvulsant) used to control seizure disorders is:
Phenytoin
24-hour homovanillic acid (HVA) is usually ordered to help in diagnosis of:
Malignant neuroblastoma
During a normal pregnancy, quantitative human chorionic gonadotropin (HCG) levels peak how many weeks after the last menstrual period?
8 to 10
Serum hCG levels peak at 8-10 weeks after the last menstrual period (LMP).
The hormone that triggers ovulation is:
Luteinizing hormone (LH)
The osmolality of a urine or serum specimen is measured by a change in the:
Freezing point
Which term describes a congenital disorder that is characterized by a split in the albumin band when serum is subjected to electrophoresis?
Bisalbuminemia
In monitoring glomerular function, which of the following tests has the highest sensitivity?
Creatinine clearance
In monitoring glomerular function, which of the following tests has the highest sensitivity?
Creatinine clearance
Detection of which of the following substances is most useful to monitor the course of a patient with testicular cancer?
Afp
Clinical assays for tumor markers are most important for:
Monitoring the course of a known cancer
Clinical assays for tumor markers are most important for:
Monitoring the course of a known cancer
The presence of C-reactive protein in the blood is an indication of:
An inflammatory process
The identification of Bence Jones protein is best accomplished by:
Immunofixation electrophoresis
The identification of Bence Jones protein is best accomplished by:
Immunofixation electrophoresis
A characteristic of the Bence Jones protein that is used to distinguish it from other urinary proteins is its solubility:
At 100°C
A characteristic of the Bence Jones protein that is used to distinguish it from other urinary proteins is its solubility:
At 100°C
lsoenzyme assays are performed to improve:
Specificity
Cholinesterase levels are generally assayed to aid in diagnosis of:
Organophosphate poisoning
Cholinesterase levels are generally assayed to aid in diagnosis of:
Organophosphate poisoning
A 10-year-old child is admitted to pediatrics with an initial diagnosis of skeletal muscle disease. The best confirmatory tests would be:
Aldolase and creatine kinase
A 10-year-old child is admitted to pediatrics with an initial diagnosis of skeletal muscle disease. The best confirmatory tests would be:
Aldolase and creatine kinase
