Increased urinary testosterone/epitestosterone ratios found in Swedish athletes in connection with a national control program. Evaluation of 28 cases.

In connection with a national anti-doping control program, including analysis of 8946 urine samples, 28 athletes were found to have delivered samples free from xenobiotic anabolic steroids but with an increased testosterone/epitestosterone (T/E) ratio (> 6). Unannounced testing of the above athletes produced 2-4 additional urine samples during the next 2-3 months. A low degree of variation of the T/E ratio, with a C.V. below 30% was found in 17 of the subjects whereas 10 had a C.V. varying from 31% to 43%. One subject with a high urinary T/E ratio (10.5) had a C.V. of this ratio of 126% and also an extremely high ratio between testosterone and LH in urine. It has been reported that non-users of testosterone have T/E ratios fluctuating around a mean with a C.V. that will not exceed 30%. We found that administration of testosterone to seven healthy volunteers resulted in urinary T/E ratios that varied with a C.V. ranging from 67% to 130% during the following 4 weeks. It is concluded that among the above 28 cases, only one can be regarded as a clear case of testosterone doping. Although the vast majority of Swedish athletes have urinary T/E ratios below six, there is a subfraction with a constant higher ratio, possibly due to genetic factors.