Legion Diagnostics

Precision

The Precision module evaluates the consistency of a measurement procedure by repeatedly testing control samples under defined conditions. Precision studies quantify how much a method's results vary when the same sample is measured multiple times — across replicates within a run, and across runs on different days. A method with poor precision produces inconsistent results even before accuracy is considered, which can undermine clinical decision-making.

Legion Diagnostics offers two precision study types: Simple Precision and Complex Precision. Simple Precision provides a rapid assessment of short-term (within-run) repeatability against a TEa-based goal or manufacturer claim. Complex Precision uses ANOVA-based variance component analysis to partition imprecision into its constituent sources, with short-term and long-term designs that are used in both verification and validation workflows.

When to Use This Module

Precision studies are required in a broad range of scenarios:

  • New method or instrument implementation — Before a new analyzer or reagent system is placed into routine use, precision must be verified to confirm that performance is acceptable for clinical use.
  • Method verification — Laboratories confirming that a manufacturer-validated method performs as specified in their specific environment must demonstrate acceptable repeatability and within-laboratory precision.
  • Method validation — When a laboratory develops or significantly modifies a method, a full precision validation is required to establish performance specifications.
  • Reagent lot changes — When switching to a new reagent lot, laboratories typically assess comparability to the existing lot (for example via a reagent lot comparison or a method comparison study), not by repeating a precision experiment.
  • Accreditation requirements — CAP (College of American Pathologists), The Joint Commission, and CLIA regulations require documented precision data as part of method validation/verification records for laboratory-developed and FDA-cleared tests.