Clinical chemistry moving exam

moving exam

Heirarchy of control

1. Elimination

2. Substitution

3. Engineering control

4. Administrative control

5. PPE

Dilution solution of common household bleach

Sodium hypochorite 1:10 (10%)

Non viscous spill contact time

15-20 minutes

viscous spills time

at least 30 minutes

Four basic waste of disposal technique

1. Flushing

2. Incineration

3. Landfill burial

4. Recycling

Biomedical waste segregation

black, green, yellow, yellow w black band, orange, red )

Black - non infectious dry

Green - non infectious wet

yellow - infectious and pathological

yellow w band - toxic chemicals waste w heavy trace of metals

orange - radioactive

red - sharps and pressurized container

Most common type of solution

%w/v

can change with temperature because it depends on the volume of the solution

Molarity

Commonly used for acid based reactions

normality

Unaffected by temperature, used when temp variation are significant

Molality

Forward pipetting

pipetting and mixing sample or reagent to another liquid

Reverse pipetting

For high viscosity

A. dispense B. aspirate

A. 45 degree angle B. 90 degree angle

Aspiration depth

1-2 mm

To deliver

Distilled water

To contain

Mercury

Polypropylene

where pipettes are made of

1st step in cleaning glasswares

pre-soak in soapy water

Acid dichromate or potassium dichromate dissolved in sulfuric or nitric acid.

Cleaning glassware

what water to rinse with cleaning glassware

type 1 or type 2

Sterilize glassware using

Dry heat oven (160-180 c for 1 ½ 2 hours)

The gold standard for clinical laboratory external qc testing

College of American Pathologist

A materianl of known value analyzed with patient samples

Control

Values assigned by the manufacturer

Assayed

QC material

a solution (usualy a serum) constituents but KNOWN, run SIMULTANEOUS WITH THE TEST, to check accuracy and precision.

Control limits are calculated from the

Mean and SD

The ideal control or reference limit is between

± 2SD

Accuracy

nearness or closeness to the true value

Precision

Ability of method to give the same result on the sample repeatedly.

Specificity

to detect an analyte without detecting others

Sensitivity

the amount of analyte in a solution to be detected even in smallest amount.

Reliability

To maintain accuracy and precision for a longer period of time.

Test validity

ability of a screening test to accurate identify diseased and non-disease individuals.

Proportion of the subject with positive test that had the disease

Positive predictive value

Measures of central tendency: (AMM)

1. Arithmetic mean

2. Median

3. Mode

Measures of Variation (SCV)

1. SD

2. Coefficient of variation

3. Variance

Most frequently used of measure of variation and help describe the normal curve

SD

QC CHARTS

1. Gaussian curve

2. Cumulative Sum Graph

3. Multi rule QC

4. Youden/twin plot (interlab qc)

5. LEVEY JENNINGS CHART

It will give the earliest indiciaton of systematic errors

CUSUM GRAPH

Recite the westgard control rules: (12, 13, 22, 41, r4, 10x)

12s - rejection or warning rule / for screening purposes

13s - random error

22s - systematic error

41s - last for consecutive, random error

10x - ten data on the same side ; systematic error

used in interlab qc, used to compare results from different laboratories

Youden/twin plot

Trend

QC slowly moving up or down for six consecutive days

qc values distributes themselves on one side or either side of the mean for six consecutive days.

Shift

Control values that are far from the main set of values highly deviating values

outliers

Uses a test chip to measure the analyte in the serum, which reacts with the reagent to produced a colored product.

Thin-Film analyzers

Which measures the light reflected from the colored layer?

Reflectance photometry

The total number of different tests an analyzer can perform

Test menu

Type of calibrator that uses one calibrator with a known value.

One point calibration

Keeps the analyzer clean, functional, and operating properly.

Preventive maintenance.

Uses three or more calibrators with different known values.

Multi-point calibration

It enjoys a semi-permeable membrane to separate protein from analytes, thus eliminating the need for manual deproteinization techniques.

ION SELECTIVE ELECTRODE - this describes the technology like the dialysis or direct ISE METHOD where a semi-permeable membrane separates protein from teh sample, avoiding manual protein precipitation steps.

The maximum number of tests or samples an analyzer can process in one hour

THROUGHPUT

Two consecutive controls greater than 2s above or below the mean. Accept or reject run?

Reject

One control above +2s, other below -2s from the mean. What does this indicate?

This is the R4S RULE, A random error.

Statistical test is used to compare the means of two methods?

Student’s T-test

It detect random error using previous values of individual patient

Delta check

Negative predictive value

The probability that a negative test indicates absence of disease.

Plots that will give the earliest indication of a shift or trend?

CUSUM

Plot best for detecting all types of QC errors?

Levey-Jennings chart

Plot best for comparison of precision and accuracy among laboratories

Youden / Twin plot

To determine get the COV and check the highest CV.

A. 12%

A trend in QC is most likely caused by:

find the cov: mean 76ml and sd=2.3

3%

When reffering to the qc results, what paremeter usually determines the acceptable range?

2SD