Setting Up the Experiment

Configure the linearity study by completing the following steps in Legion Diagnostics:

1. Laboratory and Instrument Context

Select your lab area and analyzer. Choose the assay being evaluated — the internal database will auto-populate TEa from CLIA, RCPA, or other regulatory sources for recognized analytes. For assays not in the database, enter the TEa manually using the manufacturer's package insert or your laboratory's established performance goals. Optionally record the operator, calibrator lot, and reagent lot for traceability.

2. Study Design Selection

Select Design A1 if you are preparing samples by serial dilution with a measurand-free diluent and the absolute concentration of the high sample is not known. Select Design A3 if your samples have certified or vendor-assigned concentration values.

For Design A3, additionally configure:

Components to include — select one or more of: Linearity, Accuracy, AMR verification. Accuracy and AMR are only available with Design A3.
Value assignment method — choose between Assigned Values (enter the certified concentration for each level) or Delta Pattern (specify two anchor levels whose concentrations are known; expected values for all other levels are calculated from these).
AMR bounds and proximity limits — if AMR verification is selected, enter the manufacturer's claimed AMR lower and upper bounds, and set proximity limits (as percentage or absolute values) to confirm the study challenged the full extent of the claimed range.

When to use a delta pattern: A delta pattern is appropriate when using a commercial vendor linearity kit that provides certified concentrations only at select levels (eg, Levels 1 and 3 in a 5-level panel). You designate those two levels as the primary comparison pair, and the module derives expected values for the remaining levels based on the concentration difference (delta) between the known anchor points.

3. TEa and Bias Allocation

The SEa tolerance — the acceptance window for residuals — is derived from the TEa and the configured bias allocation percentage. A higher bias allocation percentage assigns more of the total error budget to systematic error, making the linearity criterion more permissive. Most laboratories use a bias allocation of 25–50% as a starting point. Consult your laboratory's quality goals or the assay's analytical performance specifications when setting this value.

4. Data Entry

Upload your data using the standard CSV template. Each row represents one measurement and must include the following fields:

Column	Required For	Description
Sample ID	All designs	Unique identifier for each sample or specimen
Concentration Level	All designs	Identifier for each distinct concentration (eg, Level 1, Level 2)
Day	All designs	Day the measurement was performed
Replicate	All designs	Replicate number within the day and level
Relative Concentration	Design A1 only	Theoretical RC based on serial dilution ratios (eg, 0.60, 0.75, 1.00)
Expected Value	Design A3 only	Assigned concentration from certified reference materials (eg, 25.0, 100.0 mg/dL)
Measured Value	All designs	Actual concentration measured by the instrument for this replicate

CLSI EP06 minimum recommendations: At least 5 concentration levels spanning the analytical measurement range, tested in duplicate (2 replicates per day) over a minimum of 5 days. Levels should cover low, medium, and high clinically relevant concentrations and include samples at or near clinical decision thresholds.