The Athlete Biological Passport detects the effect of doping on the organism through longitudinal monitoring of biomarkers. The first quantitative analysis is performed by a software algorithm based on the Bayes theorem, taking into account previous values of the athlete. Profiles which have been found as abnormal with this technique are submitted for qualitative analysis to an expert panel regarding potential causes for the abnormality. Possible causes include analytical shortcomings, Pathologies, extremes of physiological regulation or doping.