Use of recovery and bias information in analytical chemistry and estimation of its uncertainty contribution

Determination of method trueness or, in its negative term, method bias is generally recognized as intrinsic part of method validation. However, there are still different points of view on how to estimate potential bias, whether to correct for it and how to accommodate it and its uncertainty in the uncertainty budget for a particular measurement. Based on the scientific literature as well as guidance documents from international bodies (e.g., ISO, IUPAC, Eurachem, ICH and APLAC), this review concludes that results should generally be corrected for known bias and incomplete recovery. The uncertainty of the bias forms an intrinsic part of the measurement uncertainty, even when no significant bias was observed.