[Radioimmunoassay of testosterone concentrations in hair: use in doping control]

The measurement of doping agents in hair is attractive since it offers an increase in retrospective detection of doping with these substances. Hair analysis has a wide window of detection, ranging from months to years, depending on the length of the hair shaft and provides information concerning the pattern of an individual's drug abuse. The aim of the present study was to evaluate the ability of a radioimmunological method to determine physiological concentrations of testosterone in hair. Specimens of hair were collected from four children, nine women and twelve men. None of the subjects was an athlete. Hair samples were weighed, decontaminated and digested in sodium hydroxide. The homogenates were extracted by organic solvent. After evaporation, testosterone was measured by radioimmuno-assay. Hair testosterone concentrations ranged 0.6-2.7 pg/mg, 1.8-6.4 pg/mg and 3.6-23.3 pg/mg for children, women and men respectively. This method is fast and accurate and could have applications in doping control, for screening easily numerous hair samples. GCMS is absolutely necessary to confirm results above 30 pg/mg.