Brief article at CanadianCyclist.com yesterday, pointed out by a Portland-based pal:

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.

Now … I’m not an endocrinologist, so much of what was in the published article (linked below) is beyond me, but what I got from it is that depending on this particular genetic marker, up to 40% of people without the two main alleles for this particular gene NEVER tested above the 4:1 testosterone/epitestosterone level, and the highest level reached was only 5.3:1 in the two weeks following a testosterone injection.

On the other hand, subjects with both alleles for this gene had baseline T/E ratios above the 4:1 limit, and could generate false-positives in up to 9% of test subjects in standard doping tests.

So what does this mean?

Well, in Floyd Landis’ case, if he has both genetic markers, then it’s very possible that his initial ratio of 11:1 was a true false positive. But then there’s the results of the CIR test, which did show that some of the testosterone in his system was exogenous. However, there are still enough questions about the methods of the Châtenay-Malabry lab to cast doubt on the results of that particular test.

On the other hand, riders without the particular genetic markers, could microdose with exogenous testosterone and never get caught because their T/E ratios never exceed the limits.

It is extremely important is that WADA/USADA/IOC/UCI/etc look more closely at the protocols and a) unify/standardize them across the various labs, and b) seek the truth (and justice), rather than the automatic presumption of guilt and subsequent legal battles which cast a bad light on the sport as a whole … even if this means genetic testing as part of the so-called medical passport program.

Further reading:

  1. Doping by mutant athletes undetected
  2. Journal of Clinical Endocrinology & Metabolism (March 11, 2008 issue)

Make your own judgments.