Quality Control

Front 1

Sensitivity

Back 1

is the ability of an analytical method to measure the smallest concentration of the analyte of interest.

Front 2

Specificity

Back 2

is the ability of an analytical method to measure only the analyte of interest.

Front 3

Accuracy

Back 3

the nearness or closeness of the assayed value to the true or target value.

Front 4

Precision or reproducibility

Back 4

the ability of an analytical method to giverepeated results on the same sample that agree with one another.

Front 5

Practicability

Back 5

the degree by which a method is easilyrepeated.

Front 6

Reliability

Back 6

the ability of an analytical method tomaintain accuracy and precision over an extended period of time during which equipment, reagents and personnel may change

Front 7

Diagnostic sensitivity

Back 7

is the ability of the test to detect theproportion of individuals with that disease who test positively with the test.- indicates the ability of the test to generatemore true-positive results and few false negative.

Front 8

Diagnostic sensitivity formula

Back 8

Sensitivity (%) = 100 x the number of diseased individuals with a positive test ÷ Total number of diseased individuals

Front 9

Diagnostic specificity

Back 9

- is the ability of the test to detect theproportion of individuals without the disease who testnegatively for the disease.

- it reflects the ability of the method to detect true-negative with very few false-positives

Front 10

Diagnostic specificity formula

Back 10

Specificity (%) = 100 x the number of individuals without the disease with a negative test ÷ total number of diseased individuals

Front 11

Intralab (internal QC)

Back 11

- it involves the analyses of control samplestogether with the patient specimens.

- it detects changes in performancebetween the present operation and the “stable” operation.

-detects both random and systematic errors.

Front 12

Interlab (internal QC)

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- it involves proficiency testing programsthat periodically provide samples of unknown concentration of analytes to participating laboratories.

- it is important in maintaining long-term accuracy of the analytical methods.- it is also used to determine estimates of the state-of-the-art interlaboratory performance.

- difference of >2 in the results indicates that a laboratory is not in agreement with the rest of the laboratories included in the program.

Front 13

Objectives of QC

Back 13

1. To check the stability of the machine.

2. To check the quality of reagents.

3. To check technical errors.

Front 14

Characteristics of an Ideal QC Material

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1. Resembles human sample.

2. Inexpensive and stable for long periods.

3. No communicable diseases.

4. No matrix effects/known matrix effects.

5. With known analyte concentrations.

6. Convenient packaging for easy dispensing and storage.

Front 15

5 and 20

Back 15

the different levels of control material must be analyzed between _______ days.

Front 16

mean and standard deviation (SD).

Back 16

Control limits are calculated from the ________ and ________

Front 17

human sample

Back 17

Quality control materials should resemble __________ and be available for a minimum concentrations which requires new estimates of the mean and standard deviation.

Front 18

single lot

Back 18

Use of a _______ for an extended period allows reliable interpretative criteria to be established which will permit efficient identification of an assay problem.

Front 19

Human control materials

Back 19

are preferred but because of limited sources and biohazard considerations, bovine control materials are used.

Front 20

Bovine-based QC material

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is NOT the choice for immunochemistry, dye-binding and certain bilirubin assays.

Front 21

Matrix effects

Back 21

are results of improper product manufacturing, use of unpurified human and nonhuman analyte additives and altered protein components.

Front 22

Assayed controls

Back 22

are more expensive but can be used as external checks for accuracy.Determination of the mean and SD for the unassayed controls is also advisable because this process improves the performance characteristics of statistical control procedures.