CC PART 1 Flashcards by Toni Mae Inductivo

(2) WET CHEMISTRY

A. Liquid Reagent
B. Lyophilized Reagent

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entails freezing a material at −40 °C or less and then subjecting it to a high vacuum. Very low temperatures cause the ice to sublimate to a vapor state. The solid non-sublimable material remains behind in a dried state.

Lyophilization

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In Jendrassik-Grof Method for bilirubin, caffeine and sodium benzoate serve as:

A. Color developer
B. Stopper of reaction
C. Dissociating reagent
D. Reducing agent

C. Dissociating reagent

Rationale:
● Technique for Multiple Choice Questions →
Elimination
○ Color developer (diazo reagent) ✖️
○ Stopper of the reaction (Ascorbic acid) ✖️
● Explanation: In Jendrassik Grof, B1 is attached to
the albumin. When you add a diazo, it will not
react. B1 and Albumin (Both are indirect method)
must be separated via Dissociating Reagent such
as
■ Caffeine
■ Sodium benzoate
■ Evelyn Malloy
● Reagent: 50% methanol

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Storage and stability

Reagent storage:

2-80 C

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Performance indicator that refers to the dispersion of repeated measurements around the mean

a) Accuracy
b) Precision
c) Reliability
d) Linearity

B. Precision - magkakasama yung values pero wala sa gitna

Rationale:
● Accuracy: Nearness to the true value (If it hits the right target)
● Reliability: If the machine remains both accurate and precise for an extended period of time
● Linearity: It is the reportable range of an analyte

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Long acting barbiturate used in treating generalized grand-mal tonic-clonic seizures:

a) Ethosuximide
b) Acetaminophen
c) Tacrolimus
d) Phenobarbital

D. Phenobarbital

Rationale:
● 2 types of seizure:
○ Grand mal
○ Petit mal
● NOT tacrolimus since it is an immunosuppressant
● NOT acetaminophen since it is an antipyretic

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When the spread of data in the gaussian distribution falls between +/- 2 SD, the confidence
interval is:

a) 68.3%
b) 95.8%
c) 99.7%
d) 100%

b. 95.8%

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Convert 5 dL to mL

A. 5 mL
B. 50 mL
C. 500 mL
D. 5000 mL

C. 500 mL

Rationale: 1 dL = 100 mL

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Process that guarantees that the laboratory results are accurate as possible and includes three phases of testing: Preanalytic, analytic, post-analytic

A. Quality Management
B. Quality assurance
C. Quality points
D. Quality Control

Quality Assurance

Rationale: The bigger umbrella is Quality Management. Under Quality Management is the Quality Assurance. Quality Assurance has three phases called pre-examination,
examination, and post examination. Quality Control is under the examination phase or analytical phase.

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Which of the following lipoproteins can be observed in the upper part of the evacuated tube?

A. Cholesterol
B. VLDL
C. Triglycerides
D. Chylomicrons

D. Chylomicrons

Rationale:
● If the patient does not fast, this can be observed in the upper portion of Chylomicrons
● If the sample is turbid? = VLDL
What type of triglyceride does chylomicron transport?
● Exogenous
○ For VLDL
● Endogenous
If the question would be “Which LIPID…” = The answer would be Triglycerides

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Instrument technique that measures the amount of light emitted by the excited atom

a) Atomic Absorption Spectrophotometry
b) Spectrometry
c) Flame Emission Photometry
d) Nephelometry

Flame Emission Photometry

Rationale:
● If the question would be “The amount of light…”
○ Emitted: Flame Emission Photometry
○ Absorbed by ground state: Atomic
Absorption Spectrometry
○ Transmitted: Spectrometry
○ Scattered: Nephelometry
○ Blocked: Turbidimetry

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If the quality improvment, the question “Does this process need to exist?” refers to:

A. Lean
B. Six Sigma
C. Lean Six Sigma
D. Quality Assessment

A. Lean

Rationale:
● Lean: Reduction of waste
● Six Sigma: Reduction of errors
● If combined (Lean Six Sigma): Reduction of waste
and errors

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Sa blood sample collected by the medical technologist was accidentally left at the nurse station of hours, what test can still be performed?

A. Electrolytes
B. Cholesterol
C. Triglycerides
D. Glucose

C. Triglycerides

Rationale:
● Electrolytes: Increase
● Glucose: Decrease every hour

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(2) CHEMISTRY APPROACH

1 WET CHEMISTRY
2 DRY CHEMISTRY

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NO reconstitution needed

Liquid Reagent

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Does Lyophilized Reagent Has Longer shelf life?

True or False

True

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+ Diot H2oO -> Reconstituted

Lyophilized Reagent

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Machine: Vitros

Dry Chemistry

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Machine: Cobas

Wet Chemistry

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(5) layers in Dry Chemistry

Spreading
Scavenger
Reagent
Indicator
Support

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Principle: Reflectance Photometry
- Lights are reflected

Dry Chemistry

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Validation Studies

BUN STD = 10 mg/dL

a. 11 mg/dL
b. 10 mg/dL
c. 9 mg/dL
d. AOTA

b. 10 mg/dL (Accuracy)

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Smaller volume requirement

Dry Chemistry

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(5) Reagent Considerations

Storage and stability
Reagent Distribution
Interfering Substances
Expected Values
Performance Characteristics

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Change in the Reagent Lot number:

Perform Validation Study (Recalibration)

TREND or SHIFT Using deteriorated reagent:

TREND

Trend and Shift is it Random or Systematic?

Systematic

(2) Reasons for using a calibrator/standard

1. When performing method evaluation/technical validation 2. Identification of errors in WG rule when the reagent is out of control

Must know of a medtech:

Knowledge of chemicals, standards solutions buffer and water requirements (MSDS/SDS)

(5) Reagent Deterioration

1. Turbidity and precipitation 2. Reagent fails to meet linearity claims 3. Fails to recover control value in stated range 4. Moisture has penetrated the vial and caking has occurred 5. discrepancy in the first absorbance against water either greater or less than 0.8 depending on the set wavelength

Reportable range

linearity

(3) Interfering Substances

1. Anticoagulants 2. Drugs and other substances 3. Pyridoxal Phosphate

(3) Common anticoagulants that cause interference:

1. EDTA 2. NaF 3. Oxalate

(3) Blank

1. Reagent blank 2. Sample blank 3. Water blank

If the sample is hemolyzed, lipemic, icteric what blank will you used?

Sample Black

To set spectrophotometer reading to zero ABS - % Transmission -

Water Blank ABS - 0 % Transmission - 100

Before, During, After Reagent

Before

Before, During, After Sample

During

Before, During, After Water Blank

Before

(4) Performance Characteristics

* Linearity/Analytical Measurement Range (AMR) * Comparison of methods * Sensitivity and Specificity * Precision studies

Two commercial serum controls were assayed twenty times and the following ________________ precison was obtained.

Within Run

Two commercial serum controls were assayed for five consecutive days (triplicate for each level), the following ______________ precision was obtained

Run to Run Precision

Two means

T test

highly purified chemical than can be measured directly to produce a substance of exact known concentration

Primary standard

substance of lower purity

Secondary standard

represents a specimen that is similar in composition to the patient’s whole blood or plasma. The value is known and measured the same way with the patient unknown sample.

Controls

Can you use Secondary standard alone?

(2) Controls

1. Assayed 2. Unassayed

High, Normal, Low

3 levels

Pathologic and nonpathologic

2 levels

All CC tests except Blood gases, therapeutic drugs, hormones

2 Levels

WG note: 1:2s 1:3s R:4S 2:2S 4:1S 10:X

2 Levels

● Additional Westgard rules: - 3:15 - 2 of 3:2S - 7T - 9X

3 Levels

Once in 24 hours

2 levels

Every 8 hours

3 levels

monitors overall reliability of laboratory results means of accuracy and precision

Quality Controls

Two Divisions of Quality Control:

1. Internal 2. External

Proficiency testing

External quality control

1. Analysis of control samples 2. Instrument maintenance 3. Statistical analysis

Internal quality control

Water purified by distillation, purified to remove almost all organic materials. Water is boiled, vaporized and condensed, distillation of water can be more than once.

Distilled Water

-process of removing dissolved gases by nonvolatile substances carried over steam in the distillation process or by dissolved substances from storage containers

Double Distillation

Water that is always used in Molecular biology

Double Distillation

used for tests that require Nh3 free water

Double Distillation

water purified by ion exchange ; removes some or almost all ions ;organic materials may still be present it is neither pure nor sterile ;deionized water is purified from previously pre-filtered or distilled water; produced using either an ANION or a CATION exchange resin

Deionized Water

water purified by reverse osmosis

Reverse-Osmosis

Uses pressure to pump water across a semipermeable membrane, thereby producing filtered product of the original water. Use also for pretreatment of water

Reverse-Osmosis

(4) Water Purification

1. Activated charcoal 2. Glass 3. cotton 4. submicron filter (0.2 mm)

Removes organic materials

Activated charcoal

Higher the water resistance/resistivity _______ the water purity

Higher

used in clinical chemistry (highest purity)

Type 1

acceptable for most analytic requirements including reagent, quality control and standard preparation

Type 1

acceptable for most analytic requirements

Type 2

autoclave wash water- acceptable for glassware washing but not for analysis or reagent preparation

Type 3

* utensils made of glass or plastic that are used to transfer liquids. They may be reusable or disposable

Pipets

the tip should be immersed in the liquid to be transferred to a level that will allow it to remain in the solution after the volume of liquid has entered the pipet

Design

* lean by soaking to a soapy water with the pipet tips up; -used for volumes of 20 ml or less.

Pipets

* with different tolerances depending on the volume(mL).

Pipets

Holds a particular volume but does not dispense that exact volume; delivers the amount by washing it and emptying

To contain (TC)

- Calibrated by: Mercury - Drainage characteristic: Blow-out - For viscous sample

To Contain

● Calibrated by: Water ● Drainage characteristic: Self-draining ● For non-viscous samples

To Contain

will dispense the volume indicated; transfer exact amount- do not blow the last drop; rate of flow is gravity

To deliver (TD)

(2) Drainage Characteristics

a. Blow-out b. Self-draining

- Self draining - Non viscous

To deliver (TD)

Markings are absent

Self-draining

Calibrated by: Distilled Water

To deliver (TD)

● Contains two etched rings with colored rings near the top where you place the rubber aspirator. ● Before, mouth pipetting was used but was discontinued a few years ago.

Blow-out

capable of dispensing several different volumes

Measuring or graduated

designed to dispense one volume without further subdivisions

Transfer

Serologic (graduated up to the tip)

Blow-out pipet

-self draining - full volume should be used -has dead space

Mohr (has dead space)

Pipets: According to function 1. Measuring Pipets

- Mohr - Serologic a. Sahli-Hellige b. Lang-Levy c. RBC/WBC pipet

-do not have _____________ -transfer solution or biologic fluids without consideration of ________ -maybe disposable

-do not have CALIBRATION MARKS -transfer solution or biologic fluids withOUT consideration of SPECIFIC VOLUME -maybe disposable

-do not have _____________ -transfer solution or biologic fluids without consideration of ________ -maybe disposable

Pasteur Pipet

– for preparation of ____________________________ -always ______________. - with greatest degree of accuracy and precision - most accurate pipet

Volumetric pipet (bulb is in the middle)

– for preparation of ____________________________ -always ______________. - with greatest degree of accuracy and precision - most accurate pipet - Non-viscous

– for preparation of STANDARDS/CALIBRATORS, CONTROLS AND REAGENT. -always SELF-DRAINING. - with greatest degree of accuracy and precision - most accurate pipet

-with an etched marked near the delivery tip -classified as blow-out pipette - Viscous Samples

Ostwald Folin (bulb is nearer the mouthpiece)

-with an etched marked near the _______________ -classified as ___________________

-with an etched marked near the DELIVERY TIP -classified as BLOW OUT PIPETTE - Viscous Samples

1. Single-Channel - 2. Multi-Channel -

1. Single-Channel - 1 Tip 2. Multi-Channel - Multiple Tip

Fixed Volume and ___

Variable volume

for volumes less than 1 ml -automatic implies that the mechanism that draws up liquid and dispenses it

Micropipet /Automatic pipet

1. with total holding of less than 1ml 2. may serologic or Mohr

Micropipet

QUESTION 1: Pipet with the greatest degree of accuracy and precision: A. Serologic Pipet B. Mohr Pipet C. Ostwald-Folin pipet D. Volumetric pipet

D. Volumetric pipet

§ Uses a suction aspirate & dispense sample through polypropylene tip. 1 or 2 stop. 2nd stop button is depressed to 2nd stop to “blow out”. tips can only be used once. Seals require periodic lubrication

Air Displacement

§ piston-mechanism; air movement; relies on a piston for suction creation to draw the sample into a disposable tip.

Air Displacement

§ Uses a glass capillary tip fitted with Teflon -tipped plunger. No carryover. Tips are reusable. Plunger setting must be checked & teflon tip replaced periodically

Positive Displacement

§ Piston mechanism; syringe like; operates by moving the piston in the pipet tip or barrel; much like a hypodermic syringe.; piston comes in contact with the liquid; no air-interface

Positive Displacement

QUESTION 2: Positive displacement pipet: A. With no air cushion B. Can pipet high density samples C. Aspiration force remains constant D. A, B and C

D. A, B and C

1. bottle-top 2. motorized 3. band-held 4. attached to dilutor

Dispenser pipets

Obtain from a common reservoir and dispense it repeatedly

Dispenser pipets

for automatic pipetting devices a. spectrophotometer – molar extinction coefficient of a compound is obtained or comparison of different dilution of potassium dichromate and its absorbance b. Use potassium dichromate (K2CR207), a primary standard that is readily available and has a sharp absorption peak at 350 nm.

Photometric method

done by delivering and weighing a solution of known specific gravity; such as water; most desirable method-most desirable for pipet calibration.

Gravimetric method

molar extinction coefficient of a compound is obtained or comparison of different dilution of potassium dichromate and its absorbance

Spectrophotometer

A process whereby centrifugal force is used to separate solid matter from a liquid suspension

Centrifugation

Bottle: Low actinic

Positive Displacement

supernatant – sediment –

supernatant – liquid sediment – solid

Pipet Calibration

Quarterly or Every 3 months

parts include: head/rotor, carriers, shields, motor, chamber, control panel

Centrifugation

placing the tube by exact positioning or by the exact opposite

Rule of Thumb

PURPOSE OF THE HOLE IN centrifuge machine:________________________

For speed centrifugation

Relative Centrifugal Force (RCF): ________________ Revolutions Per Minute (RPM):________________

RCF: Force Acting in the Sample RPM: Actual Speed

TWO MODELS OF CENTRIFUGE:

1. Floor-standing centrifuges 2. Bench-top centrifuges

Tube w/ gel separator: Tube w/o gel separator:

**Tube w/ gel separator: 10-15 minutes @1000-3000g RCF **Tube w/o gel separator: 10-15 minutes @1000

(2) How to obtain better separation of sample:

1. Increase Speed 2. Increase Time

(2) Influences the speed

1. Motor 2. Rotor

You can convert RPM to RCH true or false

true

**Bouyant force **Frictional force

Relative Centrifugal Force (RCF)

= 1.12X10^-5 x r x rpm2

RCF

(4) Types of Centrifuge

1. REFRIGERATED CENTRIFUGE/ULTRACENTRIFUGE 2. FIXED ANGLE 3. SWINGING BUCKET 4. CYTOCENTRIFUGE

OPERATION VERIFICATION:

1. For critical applications, RPM is checked and recorded at least monthly 2. For routine applications, RPM is checked and recorded at least quarterly.

The function of the refrigerated centrifuge is to protect the biological specimens from damaged caused by heating when centrifuge Temperature ranges down to -10 C or -20 C (-50 F or -68 F)

Refrigerator

The cups are held in a rigid position at a fixed angle. ● This position makes the process of centrifuging more rapid than horizontal-head centrifuge ● Less chance that the sediment will be disturbed when the centrifuge stop

Fixed Angle or Vertical Centrifuge

● Swinging bucket rotors have holders that swing outward in response to centrifugal force, so that the tube is held vertically when placed into or taken out of the holder, but held horizontally during centrifugation

SWINGING BUCKET / HORIZONTAL CENTRIFUGE

Characteristics of a Horizontal Centrifuge:

1. When a rest, the tubes are in VERTICAL POSITION 2. During centrifugation the tubes are in horizontal position 3. Not capable of higher speed

QUESTION 3: Which of the following is not a characteristic of a Horizontal centrifuge? A. Specimen cups are in vertical position when at rest B. The cups move to a horizontal position during centrifugation C. Capable of higher speed D. As the sample is centrifuged, the particles being sedimented travel down through the liquid to the bottom of the tube

C. Capable of higher speed

QUESTION 4: Which centrifuge is used when rapid centrifugation of solution is needed? A. Horizontal-head. B. Fixed-Angle C. Cytocentrifuge D. None of the items

B. Fixed-Angle

● Not used in clinical chemistry ● Used in histopathology ● Uses a very high-torque and low inertia motor to spread the monolayers of cells rapidly across a special slide for clinical morphologic studies.

Cytocentrifuge

depending on usage: Clean interior components with soap and water followed by freshly made 10% v/v bleach solution, including sample buckets. Wearing protective gloves, wipe interior sides and bottom, taking care when removing broken pieces of glass

Weekly or biweekly

Place two equally balanced containers into the centrifuge, cover, and operate at the most commonly used speed, listening for unusual vibrations. Check the braking mechanism to ensure a smooth, gradual stop. Check the timer of the centrifuge at 15 minutes, 10 minutes, 5 minutes, and 1 minute for the time the centrifuge motor is spinning (reaches the desired rpm until the motor shuts off) using a stopwatch

Monthly

Inspect gasket and check for wear and defects, and inspect cover latch for appropriate seal. Inspect head, head shaft, and coupling for evidence of wear, cracks in fitting, corrosion, uneven wear, and signs of fatigue. Inspect brushes for wear and replace according to manufacturer’s instructions.

Quarterly

Check the revolutions per minute at several commonly used speeds, including 3000 and 1500 rpm, while centrifuging a balanced load (after it has reached stable speed) using a tachometer aimed at the reflective strip viewed through the top of the centrifuge. If the revolutions per minute vary by more than 5%, consult the manufacturer’s instructions for solving the problem.

Quarterly

If an analog scale is provided for speed, the scale can be relabeled to match the actual speed. Lubricate the centrifuge shaft according to manufacturer’s instructions, if applicable.

Quarterly

* Used to separate serum from a blood clot-used in place of centrifugation * Filter material is made of paper cellulose and its derivatives, polyester fibers, glass and a variety of resin column material

Filtration

* filter paper differs in terms of pore size and should be collected according to separation needs * filter paper should not be used when using strong acids or bases

Filtration

* Filtrate : liquid that passes through the filter paper

Filtration

COLLIGATIVE PROPERTIES 4 properties based on the relative number of each kind of molecule present

1. Vapor Pressure 2. Freezing point 3. Boiling point 4. Osmotic pressure

(F and V) (B and O)

Decrease (F and V) Increase (B and O) ● As the freezing point decreases, the vapor pressure also decreases ● As the boiling point increases, the osmotic pressure also increases

Optically measures the level of color density corresponding to the amount of substance being tested for in the sample

Spectrophotometer

Sample is distributed evenly

Spreading Layer

Filters out substances that interfere with results

Scavenger Layer

Reagent reacts with sample

Reagent Layer

Reacted sample collects for spectral analysis

Indicator Layer

Optical interface

Support Layer

Pressure at which the liquid solvent is in equilibrium with the water vapor

Vapor pressure

Temperature at which the vapor pressures of the solid and liquid phases are the same

Freezing point

Temperature at which the vapor pressure of the solvent reaches 1 atm.

Boiling point

What are the three methods of separation?

Centrifugation, Filtration, and Dialysis

Pressure that allows solvent flow through a semipermeable membrane to establish equilibrium between compartments of different concentrations.

Osmotic pressure

method for separating macromolecules from a solvent or smaller substances

Dialysis

For critical applications, RPM is checked and recorded a. weekly or biweekly b. at least monthly c. at least quarterly

: at least monthly

What are the two operational verification activities for centrifuge set by CLSI?

1. Check timer against standardized time source (stopwatch) 2. Verification of speed

For routine applications, RPM is checked and recorded a. weekly or biweekly b. at least monthly d. at least quarterly

d. at least quarterly

Verification of centrifuge's speed is done using

using a tachometer or strobe light

Weekly or biweekly cleaning uses soap and water followed by

: freshly made 10% v/v bleach solution

Inspection of gasket and checking for wear and defects, and inspecting cover latch for appropriate seal is done a. weekly b. monthly c. quarterly

c. quarterly

Checking the braking mechanism to ensure a smooth, gradual stop is done a. weekly b. monthly c. quarterly

monthly

Checking the revolutions per minute is done a. weekly b. monthly c. quarterly

c. quarterly

What do you call the product of filtration?

Filtrate

Checking the timer of centrifuge is done a. weekly b. monthly c. quarterly

b. monthly

Used when rapid centrifugation of solutions containing small particle is needed up to 7000 rpm (slower than ultracentrifuge)

FIXED ANGLE / VERTICAL CENTRIFUGED

FIXED ANGLE / VERTICAL CENTRIFUGED Angle:

25-40