Biological variation

Question 1

1. Which of the following usually best describes the variation
   in the concentration or activity of most measurands in laboratory medicine?

a. Circadian rhythms
b. Monthly cycles
c. Systematic trends
d. Random variations
e. Seasonal fluctuations

Answer 1

d. Random variations

Question 2

2. Which of the following strategies is recommended to best
   set general analytical performance specifications?

a. Effect of analytical performance on clinical outcomes
b. Fractions of biological variation component estimates
c. Professional body recommendations
d. The limits of acceptance used in external quality assessment or proficiency testing
e. The state of the art

Answer 2

b. Fractions of biological variation component estimates

Question 3

3. Which of the following is irrelevant to the creation of Reference Change Values?

a. Within-subject biological variation
b. Analytical bias
c. Analytical imprecision
d. Preanalytical sources of variation
e. Between-subject biological variation

Answer 3

e. Between-subject biological variation

Question 4

4. What analytical imprecision should be used when the reference change value is to be created for a measurand that
   will be used by your own laboratory?

a. The analytical imprecision obtained from duplicate analyses obtained during the study of the biological variation
b. The best analytical imprecision you can obtain in your
laboratory
c. The analytical imprecision obtained in your laboratory
during same time period as the time interval between
the samples examined
d. The analytical imprecision as assessed from an external
quality assessment scheme
e. The analytical imprecision documented in the manufacturer’s literature

Answer 4

c. The analytical imprecision obtained in your laboratory
during same time period as the time interval between
the samples examined

Question 5

5. Which of the following represents the individuality of
   most measurands in laboratory medicine?

a. The index of individuality is high
b. The index of individuality is low
c. The measurand has low individuality
d. The within-subject variation is larger than the
between-subject variation
e. The analytical imprecision is lower than the within-subject variation

Answer 5

b. The index of individuality is low