Even high-tech molecular tests like PCR would be worthless unless you knew the gene delivery site, says Verma. Essentially, you'd need a full-body PCR, Verma says. "You could inject the gene in any number of places -- the muscle, the big toe, the liver, the lung, anyplace. And you could only detect it if you know where [it had been injected]. The genetic 'message' is not in the blood. The only thing we could detect in serum is that the person has more EPO [than normal]."
That might be suspicious, he says, but it isn't entirely unusual. Even in a couch potato, infections can dramatically increase red blood cells, as can traveling from low to high altitude. If somebody wanted to cheat using EPO, says Verma, there are any number of seemingly legitimate excuses to explain an usually high level. And officials would be hard-pressed to disprove them.
Right now, hGH and EPO are the most likely candidates for gene therapy abuse, Verma tells WebMD, but he doesn't rule out a host of as-yet-undiscovered agents. Researchers "could [identify] an enzyme that would give a greater degree of stamina by reducing the heart rate and allowing you to breathe more oxygen in, for example," he says. As the Human Genome Project unfolds, the list of potential performance-enhancing genes is bound to grow.
For that knowledge to become a doping tool will, of course, require collusion on the part of the medical community. Unfortunately, concedes Verma, "this happens all the time. In East Germany, when they started doing doping with steroids, it was clearly done by doctors." That might be ascribable to a totalitarian government, he says, "but in a capitalistic society, doctors might do it for the money. We're no different than [anyone else]."