Alternative markers for the long-term detection of oral testosterone misuse.

The screening of testosterone misuse in the doping control field is normally performed by the measurement of the ratio between the concentrations of testosterone and epitestosterone excreted as glucuronides (T/E). Despite the satisfactory results obtained with this approach, the measurement of T/E presents some limitations like the long-term detection of oral testosterone administration. Recently, several testosterone metabolites released after basic treatment of the urine have been reported (androsta-1,4-dien-3,17-dione, androsta-4,6-dien-3,17-dione, 17β-hydroxy-androsta-4,6-dien-3-one and 15-androsten-3,17-dione). In the present work, the usefulness of these metabolites for the detection of oral testosterone misuse has been evaluated and compared with the conventional T/E measurement. For this purpose, 173 urine samples collected from healthy volunteers were analysed in order to obtain reference concentrations for the four metabolites released after alkaline treatment. On the other hand, urine samples collected from five volunteers before and after testosterone undecanoate administration were also analysed. Concentrations of androsta-4,6-dien-3,17-dione and 17β-hydroxy-androsta-4,6-dien-3-one showed a similar behaviour as the T/E, allowing the detection of the misuse for several hours after administration. More promising results were obtained by quantifying androsta-1,4-dien-3,17-dione and 15-androsten-3,17-dione. The time in which the concentrations of these analytes could be differentiated from the basal level was between 3 and 6 times longer than the obtained with T/E, as a result, an improvement in the detection of testosterone abuse can be achieved. Moreover, several ratios between these compounds were evaluated. Some of them improved the detection of testosterone misuse when comparing with T/E. The best results were obtained with those ratios involving androsta-1,4-dien-3,17-dione.