Biologic Variations Flashcards
1
Q
What variations affect the test results of an individual person over time?
A
Pre-analytical variation (CVP)
• Analytical variation (CVA)
• Within-subject biological variation (CVI)
2
Q
What is the index of individuality?
A
• Within-subject biological variation(CVI)
• Between-subject biological variation (CVG)
II=CVI/CVG
3
Q
If II
A
population based reference range is of little use.
4
Q
If II > 1.4…
A
population based reference range is of significant value.
5
Q
Why is it important to understand biological variations?
A
- To determine the changes that occur in an individual’s serial results are SIGNIFICANT
- To determine whether population-based reference values are useful for interpretation of test results of individual patients
6
Q
What are biological variations?
A
- Within-subject variation
- Between-subject variation
- Most analytes do not have cyclical rhythms that are of major clinical importance.
7
Q
What is the reference change value?
A
RCV = z x square root of 2 x sqr(CVa^2 + CV1^2)
