Update of Standard Practices for New Method Validation in Forensic Toxicology

International agreement concerning validation guidelines is important to obtain quality forensic bioanalytical research and routine applications as it all starts with the reporting of reliable analytical data. Standards for fundamental validation parameters are provided in guidelines as those from the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), the German speaking Gesellschaft fur Toxikologie und Forensische Chemie (GTFCH) and the Scientific Working Group of Forensic Toxicology (SWGTOX). These validation parameters include selectivity, matrix effects, method limits, calibration, accuracy and stability, as well as other parameters such as carryover, dilution integrity and incurred sample reanalysis. It is, however, not easy for laboratories to implement these guidelines into practice as these international guidelines remain nonbinding protocols, that depend on the applied analytical technique, and that need to be updated according the analyst's method requirements and the application type. In this manuscript, a review of the current guidelines and literature concerning bioanalytical validation parameters in a forensic context is given and discussed. In addition, suggestions for the experimental set-up, the pros and cons of statistical approaches and adequate acceptance criteria for the validation of bioanalytical applications are given.