analytical method validation

Analytical method validation is the work of proving that a test actually measures what it claims to, reliably enough to make decisions on. Before you trust a result that decides whether a batch passes or fails, you first show the measuring tool is trustworthy — much like calibrating a scale before weighing valuables.

Validation evaluates a defined set of performance characteristics. Accuracy checks closeness to the true value; precision checks repeatability and reproducibility; specificity confirms the method measures the analyte without interference from impurities or excipients; linearity and range define where results stay proportional and usable; and limits of detection and quantitation matter for trace tests like impurities. Robustness probes how small, deliberate changes in conditions affect results, and the requirements differ by method type (an assay, an impurity test, an identification, or a dissolution method each emphasize different characteristics).

International guidance, notably the ICH framework, defines these characteristics and which apply to each kind of method. Validation is distinct from system suitability and routine verification: validation establishes the method is fit for purpose once, while ongoing checks confirm it keeps performing each time it is run.