QCATLAS QC TOOL
Sigma Metric Calculator
Measure analytical performance using your TEa, bias, and imprecision data.Sigma
=
TEa − |Bias|
CV
01
Enter performance data
Use percentages for all three values.02
Performance position
Your result is mapped to the sigma scale.SIGMA METRIC
—
Awaiting dataExcellent
≥ 6σ
Good
4–<6σ
Marginal
3–<4σ
Poor
<3σ
σ —
InterpretationEnter your data to view the analytical
performance category.
Important:
Sigma is an analytical performance indicator. QC rules and
frequency should also reflect clinical risk, method stability,
and laboratory policy.