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Detecting doping in sports

DISGRACED CYCLIST Floyd Landis was formally stripped of his 2006 Tour de France title recently, making him the latest athlete felled by a doping scandal. Landis's routine urine test had shown an abnormally high ratio of testosterone to epitestosterone. Further testing showed the testosterone contained a high proportion of carbon isotope derived from soybeans - indicating it was synthetic and not natural.

Observers may be forgiven if they can't follow the arcane details of antidoping tests. The testers themselves sometimes get confused. In 1988, for example, Canadian sprinter Ben Johnson was taking growth hormone, testosterone, Dixarit, Furazabol, and inosine, yet was nailed for supposedly taking stanazolol, which according to one report, was "the only illegal drug he hadn't used."

Traditionally, authorities and organizations have tested athletes' urine for specific banned substances. The National Football League, for example, specifies dozens of prohibited anabolic steroids, and performs numerous yearly checks on players for these drugs.

Unfortunately, this strategy is riddled with problems.

First, as with Johnson's saga, the sheer number of tests increases the possibility of a single error. Second, steroid dopers remain a few steps ahead of the testers by continuously inventing new drugs. Finally, some performance enhancing drugs can't be identified by technology. Most notably, synthetic growth hormone, which has been around for almost three decades and widely thought to be used by baseball player Barry Bonds, can't be told from natural growth hormone.

There's a better way to detect doping that relies on a more advanced detection system: the human body. All human hormones - including steroids like testosterone - are controlled by natural feedback loops, much like a thermostat controls a furnace switch. When it's cold in a house, a thermostat turns on the furnace, and when the temperature rises, turns it off. Now pretend you "dope" some houses with space heaters. You can easily tell what houses are "performance enhancing" by checking how often the built-in furnace turns on.

Similarly, when an athlete uses anabolic steroids or human growth hormone, the brain turns off the signal to produce natural hormones. These signals - called lutenizing hormone and follicle-stimulating hormone in the case of anabolic steroids - can be measured. Since the precise kind of steroid doping is irrelevant (just as the brand of space heater is irrelevant) one could simply measure a handful of feedback hormones instead of dozens on specific banned drugs.

That's also why many endocrinologists couldn't understand the uncertainty over Bonds's alleged use of growth hormone. A simple blood test looking for suspicious levels of a feedback hormone called IGF-1 would provide evidence for growth hormone doping.

The presence of abnormal feedback doesn't provide a smoking gun for doping, since the exact types of drugs aren't identified. According to Dr. Timothy Noakes, who wrote about sports doping in the New England Journal of Medicine in 2004, an abnormal lutenizing hormone and follicle-stimulating hormone "certainly would show that an athlete was using anabolic steroids but since the exact drug was not identified, the athlete would not be able to be prosecuted."

However in a major shift, use of these so-called indirect markers was endorsed by the World Anti-Doping Agency in 2003. According to Olivier Rabin, the agency's science director, indirect markers are "really what we are developing now," and tests for IGF-1, lutenizing hormone, and follicle-stimulating hormone could become standard in several years. Additionally, Rabin endorsed the concept of an "athlete's passport," where hormone levels would be tracked over long periods of time to establish an individual's baseline and then assess for any sudden shifts.

The agency's approach has attracted over 500 worldwide signatories from international soccer teams, the Olympics, and is supported by dozens of governments. Yet according to Rabin, no major US professional sports league has yet signed on to the World Anti-Doping code.

For many athletes, it's hard to resist the allure of drugs that can shave 4 seconds off one's 400 meter run or add 60 feet to one's discus throw. And the larger questions of what constitutes natural or artificial talent still loom. But for now, if we all do agree that performance enhancing drugs are unfair, then we at least should demand reliable enforcement.

Darshak Sanghavi is a pediatric cardiologist at the UMass Medical School and author of "A Map of the Child: A Pediatrician's Tour of the Body."  

Copyright 2007 The New York Times Company