New drug tests try to keep up with athletes

Professional sports leagues are getting an assist from science in their crackdown on athletes' use of performance-enhancing drugs.

But testing for performance-enhancing substances is not easy. Detecting these drugs is sort of like finding a patch of man-made snow on a white-capped mountain: Many of these substances are similar or identical to compounds made naturally by the body, and it can be frustratingly difficult to prove that a compound found in the body is not natural.

Recently, however, several important technological advances have greatly improved detection methods for a number of drugs, including the natural steroid hormone testosterone; erythropoietin, a drug that raises the red blood cell count; and newly developed ''designer steroids" -- modified versions of existing steroids developed entirely on the black market. While the new tests are still not perfect, they will make it more difficult for future athletes to gain an unfair advantage.

''It's warfare out there," said Dr. Don Catlin, director of the UCLA Olympic Analytic Laboratory, which oversees drug testing for professional football, baseball, Olympic athletes, and amateur athletes. ''They'll always be working on new drugs," he said. ''And we'll always be working on ways to detect these things as soon as they come out."

The stakes are high: Testing must be highly accurate because an athlete's reputation -- and even career -- rests on the outcome.

''When the result of your test can change an athlete's livelihood, you've got to be 100 percent right," Catlin said.

One of the most important breakthroughs over the past few years has been a new technique to more accurately detect the use of testosterone, a so-called ''anabolic drug" that is believed to increase muscle mass. (Few studies have documented that testosterone actually increases muscle mass, but strong anecdotal evidence suggests that it does.) Detecting the use of testosterone is tricky because testosterone is made naturally by the body, and it is hard to differentiate natural testosterone from the drug form.

Researchers developed a test that takes advantage of a slight difference between natural testosterone and the drug form. For reasons that are not entirely understood, a molecule of testosterone produced by the body has a distinctive weight that is slightly different from the weight of a molecule of testosterone taken in drug form.

A relatively new urine test for testosterone can distinguish between the natural and the drug forms by calculating the weight of the average testosterone molecule. According to Catlin, this test has virtually eliminated testosterone use by top athletes.

Another recent breakthrough is a test for a drug called erythropoietin (sometime called epo), a substance that is also naturally made by the body. Erythropoietin was developed in the late 1980s to treat selected patients with anemia due to kidney disease. Endurance athletes quickly realized, however, that they too could use the drug to increase their blood counts, which might result in improved performance.

A few years ago, researchers developed a test that exploits one of the small differences between natural erythropoietin and the drug form. Synthetic and natural erythropoietin create a slightly different pattern when their molecules are separated based on weight and electrical charge.

The new urine test has been refined considerably since it first came out in 1999, and in 2002 a test for a longer lasting cousin of erythropoietin called darbepoetin was developed. The tests are still very expensive and time-consuming to run, though, and more work will be needed. Still, erythropoietin use by athletes has dropped dramatically over the past few years.

Several other challenges loom.

One concern is the recent appearance of ''designer drugs" like THG, an anabolic steroid that experts believe began to be used secretly by athletes in about 2003. Mainstream scientists did not realize the drug existed until an anonymous source sent a sample containing THG to Catlin's lab in Los Angeles. Catlin and his colleagues quickly identified THG and developed an accurate test for the drug.

Other new substances have recently appeared as well, and more are sure to follow suit.

''Medical scientists are always having to play catch-up," said Dr. Peter Snyder, an endocrinologist at the University of Pennsylvania.

Another problem is how to detect substance use in athletes who stop taking drugs a few days before drug testing. Many of these substances last only a very short time in the body, and if an athlete finds out about a drug test even a short time beforehand, he or she can avoid a positive test simply by temporarily stopping the drug.

To prevent this, researchers are currently looking at ways to detect drug use when the actual substance is no longer present in the urine or blood.

''We believe that the long-term use of steroids leave footprints in the sand," Catlin said. ''If we could figure that out better, it would be a quantum leap forward."

According to Dr. Arnold Mazur, a physician at Boston College who is affiliated with the drug testing and education program for intercollegiate athletics, the biggest challenge at the amateur level will be to increase the number of drug tests that are conducted.

Most amateur athletes cannot afford the high price tag for the newest, difficult-to-detect substances, so the relatively inexpensive standard tests will be enough to catch virtually all the cheaters.

But at higher levels of competition, the only way to end substance use will be to keep pace with the ever-expanding list of substances athletes take to get ahead.

''Taking performance-enhancing substances is worth it to some of these top athletes because they can make a lot of money by being just a little bit better," Mazur said. ''But the more testing that goes on and the more that people are involved, the less the problem will be."