Specificity

The ability of an analytical procedure to measure the analyte unequivocally in the presence of components that may be expected to be present, such as impurities, degradation products, excipients and matrix (ICH Q2). It is shown with spiked samples, samples from forced degradation or comparison with an orthogonal method. ICH Q2(R2) treats specificity and selectivity together. For complex molecules such as bispecific antibodies or antibody-drug conjugates, Japanese documents also use the word for showing that an assay captures the intended target or activity.