Table 3 Proposed stepwise validation path for Alzheimer’s disease biomarkers
Parameter | Definition |
|---|---|
Robustness | The ability of a method to remain unaffected by small variations in method parameters |
Precision | The closeness of agreement between independent test results obtained under stipulated conditions |
Trueness | The closeness of agreement between the average value obtained from an extensive series of test results and an accepted reference value |
Uncertainty | A parameter associated with the result of a measurement that characterizes the dispersion of the values could reasonably be attributed to the measurand |
Limits of quantification | Highest and lowest concentrations of analyte that have been demonstrated to be measurable with acceptable levels of precision and accuracy |
Dilutional linearity | Dilutional linearity is performed to demonstrate that a sample with a spiked concentration above the ULOQ can be diluted to a concentration within the working range and still give a reliable result |
Parallelism | Relative accuracy from recovery tests on the biological matrix or diluted matrix against the calibrators in a substitute matrix |
Recovery | The recovery of an analyte in an assay is the detector response obtained from an amount of the analyte added to and extracted from the biological matrix, compared to the detector response obtained for the true concentration of the analyte in the solvent |
Selectivity | The ability of the bioanalytical method to measure and differentiate the analytes in the presence of components that may be expected to be present |
Sample stability | The chemical stability of an analyte in a given matrix under specific conditions for given time intervals |