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Clinical Chemistry 48: 629-636, 2002;
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(Clinical Chemistry. 2002;48:629-636.)
© 2002 American Association for Clinical Chemistry, Inc.

Detection of Epitestosterone Doping by Isotope Ratio Mass Spectrometry

Rodrigo Aguilera1, Caroline K. Hatton1 and Don H. Catlin1,2a

1 UCLA Olympic Analytical Laboratory, Department of Molecular and Medical Pharmacology, and
2 Department of Medicine, University of California, Los Angeles, Los Angeles, CA 90025-6106.

aAddress correspondence to this author at: UCLA Olympic Analytical Laboratory, 2122 Granville Ave., Los Angeles, CA 90025. Fax 310-206-9077; e-mail dcatlin{at}ucla.edu.

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}13C values for urinary epitestosterone. Sample preparation included deconjugation with ß-glucuronidase, solid-phase extraction, and semipreparative HPLC. Epitestosterone concentrations were determined by gas chromatography-mass spectrometry for urines obtained from a control group of 456 healthy males. Epitestosterone {delta}13C values were determined for 43 control urines with epitestosterone concentrations >=40 µg/L (139 nmol/L) and 10 athletes’ urines with epitestosterone concentrations >=180 µg/L (624 nmol/L), respectively.

Results: The log epitestosterone concentration distribution was gaussian [mean, 3.30; SD, 0.706; geometric mean, 27.0 µg/L (93.6 nmol/L)]. The {delta}13C values for four synthetic epitestosterones were low (less than or equal to -30.3{per thousand}) and differed significantly (P <0.0001). The SDs of between-assay precision studies were low (<=0.73{per thousand}). The mean {delta}13C values for urine samples obtained from 43 healthy males was -23.8{per thousand} (SD, 0.93{per thousand}). Nine of 10 athletes’ urine samples with epitestosterone concentrations >180 µg/L (624 nmol/L) had {delta}13C values within ± 3 SD of the control group. The {delta}13C value of epitestosterone in one sample was -32.6{per thousand} (z-score, 9.4), suggesting that epitestosterone was administered. In addition, the likelihood of simultaneous testosterone administration was supported by low {delta}13C values for androsterone and etiocholanolone.

Conclusions: Determining {delta}13C values for urinary epitestosterone is useful for detecting cases of epitestosterone administration because the mean {delta}13C values for a control group is high (-23.8{per thousand}) compared with the {delta}13C values for synthetic epitestosterones.




The following articles in journals at HighWire Press have cited this article:


Home page
 Br. J. Sports. Med.Home page
C Saudan, N Baume, N Robinson, L Avois, P Mangin, and M Saugy
Testosterone and doping control
Br. J. Sports Med., July 1, 2006; 40(suppl_1): i21 - i24.
[Abstract] [Full Text] [PDF]


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