Legion Diagnostics

Calibration Verification & Linearity

The Calibration Verification & Linearity module confirms that a measurement procedure produces results that are directly proportional to the true concentration of the measurand across the claimed analytical measurement range (AMR), and — where applicable — verifies that the calibration of the measurement system is performing within acceptable limits. A linear, well-calibrated method means that when a patient's true concentration doubles, the reported result doubles as well — making results reliable for both clinical decision-making and patient monitoring over time.

Legion Diagnostics supports two study designs per CLSI EP06: Design A1 (a dilution study using relative concentrations) and Design A3 (a study using samples with assigned or known concentrations). Design A3 also enables optional accuracy and AMR verification, making it the more comprehensive evaluation. The appropriate design depends on whether the laboratory has access to samples with certified reference concentrations.

When to Use This Module

A linearity verification study is required or strongly recommended in the following situations:

  • New instrument or analyzer implementation — Before a new analyzer enters routine use, linearity must be verified to confirm that the measurement procedure produces proportional results across the full analytical measurement range.
  • Method or reagent system change — When switching to a new reagent system, platform, or manufacturer, a linearity study documents that the new method maintains linear response characteristics within the claimed range.
  • Verification of manufacturer claims — End-user laboratories must verify that the manufacturer's stated linearity interval holds under their specific conditions, including their reagent lots, operators, and environment.
  • Periodic quality assurance — Some laboratory accreditation programs require ongoing documentation of linearity as part of a continuous quality assurance program.
  • Accreditation requirements — CAP and CLIA require documented linearity verification data as part of the method validation and verification record for any quantitative test in routine use.