Confirmatory reanalysis of incurred bioanalytical samples.

Bioanalytical methods used to support the drug development process are validated to ensure that they function in the manner in which they are intended. "Incurred" or study samples can vary in their composition when compared with the standards and quality control samples used to validate the method and analyze these samples. During the 3rd American Association of Pharmaceutical Scientists(AAPS)/Food and Drug Administration(FDA) Bioanalytical Workshop, it was suggested that the reproducibility in the analysis of incurred samples be evaluated in addition to the usual prestudy validation activities performed. This manuscript provides recommendations concerning the number and types of samples that should be analyzed in such an evaluation, as well as the manner in which the resultant data should be analyzed. Suggestions as to follow-up activities and data reporting are also discussed. This approach is at best a beginning and is offered as a platform for future discussion, comments, and revision.