For many years, the FDA guidance on bioanalytical method validation (BMV), issued by the CDER in 2001, has been the Holy Grail for laboratories which deal with the pharmacokinetic analysis of drugs and their metabolites in clinical trials. A revised version has been expected since the EMA issued its guideline on BMV in 2012. Stephan Wnendt of MLM Medical Labs GmbH summarises the new FDA draft guidance, and considers its implications for clinical studies.