Table 6 Recommended analytical criteria for biomarker development
Validation factor | Definition [277] |
|---|---|
Accuracy | Level of agreement between biomarker and standard measure of disease presence/outcome |
Bias | Repeated biomarker measurements do not result in under/overestimation of disease activity |
Repeatability | Precision of biomarker under standard "unchanged" conditions e.g. between batches |
Intermediate precision | Precision of biomarker test in spite of laboratory variations e.g. time analysed, operator, equipment, calibration |
Reproducibility | Precision of biomarker test between laboratories with potential variability in operators and measuring systems |
LoD | The smallest amount of analyte that can be detected with a specified probability |
LoQ | The smallest amount of analyte that can be quantitatively determined with acceptable precision |
Linearity | Measured quantity values are directly proportional to the amount of biomarker in the experimental matrix |