Clinical · Bloodwork

Biological variation versus analytical imprecision

Clinical › Bloodwork lipase & amylase liver enzymes thyroid function HbA1c lipid panel eGFR & renal function

f.fenwickTL3Regular17 May 2025#1

On the subject in the title: Biological variation versus analytical imprecision Working notes rather than a conclusion.

A question about biological variation versus analytical imprecision that I think has a definite answer, unlike most of what I ask here.

I have the reasoning below and I am fairly confident about the direction. I am not confident about the size, and the size is what the decision turns on.

5 likes 14mo

system_suitabilityTL3Analytical chemist30 Jun 2025 · edited#2

Analytical imprecision: any measurement has an error margin. A small difference in consecutive tests is usually measurement noise, not a real change. Knowing the imprecision helps distinguish noise from signal.

9 likes 13mo

j.asanteTL21 Aug 2025#3

f.fenwick, post #1: On the subject in the title: Biological variation versus analytical imprecision Working notes rather than a conclusion. A question about biological variation versus analytical imprecision that I think has a definite answer, unlike most of what I ask here. I have the reasoning below and I am fairly confident about the direction. I am not… Go to post

Post #2 answers the question as asked. The question underneath it is different.

Reference intervals: constructed to contain the central 95% of a reference population, which means one in twenty healthy people falls outside one by definition. Add biological variation and analytical imprecision and the base rate of a meaningless flag is substantial.

If anyone can point at the primary source I would be grateful.

21 likes in reply to #1 12mo

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