ESTABLISHING A KETOCONAZOLE SUPPRESSION TEST FOR VERIFYING TESTOSTERONE ADMINISTRATION IN THE DOPING CONTROL OF ATHLETES

The ratio of urinary testosterone (u-T) to epitestosterone (T/EpiT) is used to disclose testosterone (T) administration in the doping contro l of sports, and a ratio greater than 6 constitutes an offence. Nevert heless, the possibility of biological outliers must not be discounted, and the use of ketoconazole has been suggested for a dynamic test to distinguish between such athletes and those using T. In this investiga tion, ketoconazole was administrated to three groups of T-pretreated a nd two groups of untreated healthy male subjects. The subjects in one of the pretreated groups were patients with mild hypogonadism. One unt reated group consisted of athletes that had been tested three times wi th high urinary T/EpiT levels. The effects of ketoconazole administrat ion on serum T (s-T) level and urinary T/EpiT ratio were monitored eve ry 2 h for an 8-h period and clearly separated T-pretreated and untrea ted subjects into two clusters (P < 0.0001). The T/EpiT ratio increase d and the s-T level remained unchanged in pretreated individuals durin g the ketoconazole test, whereas T/EpiT decreased by 60% and s-T by al most 90% in untreated subjects. The statistical power of the test incr eased by using several time points and combining the urinary T/EpiT wi th the s-T data. In conclusion, the ketoconazole test is suitable as a supportive dynamic test for the urinary T/EpiT ratio measurements in the doping control of athletes.