Table 2.

Laboratory biomarker classification for assay validation characteristics purposes ¹⁷  (provides examples, not all‐inclusive list)

Analytical technology category (example)	Assay characteristics	Assay controls and requirements
Definitive assay example (mass spectrometry)	Accuracy, trueness (bias), precision, sensitivity, LLOQ; ULOQ, specificity, dilution linearity, parallelism, assay range	Requires calibrators and uses a regression model to calculate absolute values for sample with an unknown amount of analyte
Relative quantitative assay example: LBA	Precision, trueness (bias) reproducibility, sensitivity, LLOQ; ULOQ, specificity, dilution linearity, parallelism, and assay range	Requires a standard curve and low/medium/high controls; quantitation is relative not absolute
Quasi‐quantitative assay (flow cytometry)	Precision, sensitivity, specificity, and assay range	No calibration standard, a continuous response as a characteristic of a test sample
Qualitative assay (IHC)	Reproducibility, sensitivity, and specificity	Discrete scoring scales or binary outcome (yes/no)

IHC, immunohistochemistry; LBA, ligand‐binding assay; LLOQ, lower limit of quantification; ULOQ, upper limit of quantification.