[Methodologies used to screen for doping agents]

The detection of doping agents is a major challenge due both to the large number of compounds involved, their structural diversity, and to the sensitivity thresholds required in a small volume of urine. In addition, laboratories are requested to delivery their reports within a short delay. Mass spectrometry "ion trap" and "high-resolution" methods can be used to screen for xenobiotics at the required sensitivity levels. The search for endogenous substances used as doping agents is more complex: here the difference between physiological production and exogenous input must be recognized. Isotopic mass spectrometry appears to provide a means of resolving this problem for compounds with a low molecular mass such as steroids. Search for peptide hormones is limited to erythropoietin, with the exception of quantification procedures for human gonadotropin chorionic hormone. Direct urine screening is however a long costly operation which does not always produce interpretable results. Indirect detection using hematological and biochemical parameters can only provide presumptive proof.