Canadian Cyclist


April 14/08 2:49 am - Anti-doping Tests Flawed According to Study

Posted by Editor on 04/14/08

Anti-doping Tests Flawed According to Study

The current issue of The Journal of Clinical Endocrinology & Metabolism contains a study by a Swedish team that concludes current standard anti-doping tests for steriods will not catch many athletes that used the banned substances, and will provide false positives for as many as 14% of those tested.

Anti-doping tests look for synthetic testosterone by measuring the ratio of testsoterone to epitestosterone in urine. If the ratio exceeds four to one (4:1) then it is considered an indication of doping (extra testosterone has been administered through steriod use). It was this particular test that led to Floyd Landis being stripped of his 2006 Tour de France title, when his ratio was found to be as high as 11:1.

The study, conducted at the Karolinska Institute, showed that people vary genetically in their ability to secrete the testosterone enyzme, and therefore may not show excess ratios, despite having used steriods. Over two-thirds of people from an East Asian background showed the gene variant which would allow them to pass an anti-doping test despite using steriods.

Further, the study found a gene that can lower the level of epitestosterone in urine, leading to higher ratios and false positive results. The study says that these mistakes can be cleared by further testing.

WADA (World Anti-Doping Agency) is reviewing the results of this study, and may have to revise or augment current testing procedures.

Further reading:

The Author Manuscript can be found at the Journal of Clinical Endocrinology & Metabolism (March 11, 2008 issue) Here:

Jenny Jakobsson Schulze, Jonas Lundmark, Mats Garle, Ilona Skilving, Lena Ekstrõm, and Anders Rane
Doping Test Results Dependent on Genotype of UGT2B17, the Major Enzyme for Testosterone Glucuronidation


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