News blog

Drug testing: one size doesn’t fit all

A study by Swiss researchers published this week [Br. J. Sports Med doi:10.1136/bjsm.2008.056242 (2009)], is focusing media attention on the inflexibility of a test that screens for testosterone abuse, but fails to flag up some cheats. The problem was not unknown: drug testers are already taking steps to counter it. As a commentary and editorial [subscription required] in Nature pointed out last August, there may also be flaws with more stringent steroid analyses – the ones that are actually used in court to charge athletes with doping.

The screen in question measures the ratio of testosterone to its close relative, epitestosterone, in urine. Too much testosterone and your sample is flagged up for further, more sophisticated, isotope analyses. The problem is that due to genetic variation, some athletes can use testosterone without ever breaching a fixed alert threshold ratio set in 2004 by the World Anti-Doping Agency (WADA).

To drive this home, Christophe Saudan and his colleagues tested 171 football players from various nations, and found that Asians in their sample – most of whom had a crucial genetic deletion – naturally secreted lower levels of testosterone in their urine, so were more likely to slip under the radar screen than African, European or Hispanic individuals. A unique and non-specific threshold is ‘not fit for purpose,’ the researchers say.

Fortunately, drug testers are aware of this problem.


Already, the International Cycling Union (UCI) is piloting an ‘athlete’s passport’ scheme – which builds up a record of an individual’s baseline profile, against which any deviations can be compared [New Scientist, Scientific American]. This is exactly what Saudan et al. recommend. WADA is not connected to this trial, but told the BBC last month that it was close to setting up its own athlete passport system. (Whether these ideas work in practice, of course, we’ll have to wait and see).

Donald Berry, a biostatistician from the University of Texas, in Houston, reckons that doping analyses in general have another difficulty. The rate of false positives and false negatives for the sophisticated isotope tests – the ones that actually charge athletes with cheating – have not been rigorously verified, he says (Nature 454, 692, (2008)). And the closed systems used by anti-doping agencies prevent any statistical validation. (WADA reject these arguments).

‘If conventional doping testing were to be submitted to a regulatory agency such as the US Food and Drug Administration to qualify as a diagnostic test for a disease, it would be rejected,’ Berry writes.

Comments

  1. Report this comment

    Testosterone Replacement Therapy said:

    It’s a losing battle as far as I’m concerned, and we have far more important things to worry about in society than the “sanctity of sport”. It’s not even about health anymore.

    The athletes are ahead of the testers for the most part. World records in track and field are especially inflated.

    Is it thought as cheating if a scientist takes amphetamine to garner grants or wins the Nobel Prize? It’s not something too many have thought or care about. Why should sports be any different.

Comments are closed.