The 2014 World Anti-Doping Agency (WADA) Prohibited List shows testosterone and epitestosterone listed as class S1.1a and S1.1b, with its use banned in and out of competition [1]. Doping with testosterone is suspected if the urinary ratio of testosterone over epitestosterone (T/E) exceeds 4 [2]. According to the 2012 (WADA) laboratory statistics, elevated testosterone based on the testosterone ...

BACKGROUND Epitestosterone is prohibited by sport authorities because its administration will lower the urinary testosterone/epitestosterone ratio, a marker of testosterone administration. A definitive method for detecting epitestosterone administration is needed. METHODS We developed a gas chromatography-combustion-isotope ratio mass spectrometry method for measuring the delta(13)C values fo...

Testosterone administration to male athletes can be safely detected in the vast majority of cases by the urinary excretion ratio of testosterone to epitestosterone glucuronides (TG/EG), which may not exceed 6. Some rare cases of physiologically high TG/EG ratios (between 6 and 12) are encountered; these may be attributed to a dysregulation of the testicular secretions of epitestosterone which i...

Testosterone and epitestosterone are endogenous steroids that differ in the configuration of the hydroxyl-bearing carbon at C-17. Testosterone is the predominant male sex hormone, whereas the role of epitestosterone is largely unclear. In humans, both androgens are excreted mainly as glucuronide conjugates and the urinary ratio of testosterone to epitestosterone (T/E), used to expose illicit te...

Determination of the ratio of testosterone to epitestosterone (T/E) in urine is used to detect testosterone administration in athletes, with a ratio > 6 considered as evidence of an offense. We show that administration of ketoconazole, which inhibits testosterone biosynthesis, may be useful for differentiating between an athlete who is using testosterone and one who naturally gives a ratio > 6....

A highly specific method is described for measuring the testosterone:epitestosterone ratio in equine urine by gas chromatography-mass spectrometry (GC-MS) with stable isotope internal standards. The procedure was based on Serdolit Pad-1 resin extraction, enzymatic hydrolysis, and chemical derivatisation prior to instrumental analysis. The mixed derivatives, 3-trimethylsilyl-17-pentafluorophenyl...

OBJECTIVE Testosterone is a commonly abused androgen in sports and in the gym culture of the society. Its abuse is conventionally disclosed by urinary assay of the testosterone/epitestosterone (T/E) glucuronide ratio, which should not exceed 4. A noteworthy number of athletes, however, have higher natural ratios than 4, most likely because of decreased excretion of epitestosterone glucuronide. ...

A new, relatively simple method for simultaneous determinations of urinary testosterone and epitestosterone is described. The novel feature is the periodic oxidation of testosterone and epitestosterone glucuronides with sodium metaperiodate. The chromatographic purification of the ether extracts consisted of alumina-column chromatography, followed by thin-layer chromatography on silica gel of f...