Statistics in Clinical Chemistry and Quality Control Flashcards Preview

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Flashcards in Statistics in Clinical Chemistry and Quality Control Deck (31):
0

Limited number of values

Categories

1

Used with 2 or 4 control measurements per run

Westgard Rules

2

Sum of all results divided by the number of results

Mean

3

Amount of variation

Coefficient of variation

4

Protein in urine

Ordinal scale

5

Uses a single criterion or single set of control limits

Single-rule Quality Control

6

Value that occurs most frequently in the data set

Mode

7

Locator

Finds a requested percentile

8

Warning rule to trigger careful inspection of the control data in Westgard multirule Quality Control

1(2s)

9

Things we measure and count

Variables

12

Variables can take on values in a quantitative range with defined differences between points

Interval scale

12

50th percentile

Median

12

Reject when 10 consecutive control measurements fall on one side of the mean

10(x) violation

13

Probability that the true value falls into a category

Confidence interval

13

Lowest value that an assay can reliably detect

Sensitivity

14

Reject when 2 consecutive control measurements exceed the same +/- 2s control limit

2(2s) violation

18

Accuracy is tested by ______ and ______.

Assaying patient specimens
Assaying interlaboratory survey materials with known values

19

Analytic specificity is characterized by _____ and _____.

Determination of interferences
Non-specific responses to other analytes

20

Ability to measure only the sought for analyte

Analytic specificity

21

Uses a combination of decision criteria

Multirule Quality Control

22

Scale with specific values but without equivalent distances between categories

Ordinal scale

23

Control rule when the control limits are set as the mean +/- 3s

1(3s)

24

Extent of random variation

Standard deviation

25

Decision criteria

Control rules

26

Variables can take on a limited number of values

Nominal scale

27

Chart with control limits mean +/- 2s or mean +/- 3s

Levey-Jennings Chart

28

Spread of data in which elements are distributed symmetrically around the mean

Gaussian distribution

30

Reject when 1 control measurement in a group exceeds the mean + 2s and another exceeds the mean - 2s

R(4s)

31

4(1s) violation rejects

when 4 consecutive control measurements exceed the same mean +/- 1s control limit

39

The ability to correctly detect and quantify and analyte

Accuracy

41

Precision is

the reproducibility of an assay