By Andrea Carter
They seem to be dropping like flies. This week another professional athlete, tennis player Martina Hingis, is leaving the game after she tested positive for cocaine, while in September, Floyd Landis stepped down as the Tour de France winner, suspended from competing for two years due to a doping violation.
In both cases the athletes deny the charges. However, the testers stand by their results. Drug testing in professional sports is forensic-tight. The testing technology goes down deep to the molecular level to find the answers.
“There are no false positives,” says Dr. Don Catlin, Director of the University of California Los Angeles Olympic Analytical Laboratory. “We can’t be wrong.”
In 1999 the World Anti Doping Agency was established to fight illegal drug use in professional sports. It monitors and provides stringent regulation in drug testing. Currently there are thirty-three accredited WADA labs in the world. The United States has two, one in Los Angeles and the other at the University of Utah.
Much of the testing targets the performance enhancing drugs. Common culprits are synthetic testosterone that athletes take to build muscles and erythropoietin that builds endurance by increasing red blood cell numbers to carry oxygen. However, stimulants such as cocaine and even alcohol are on WADA’s banned list.
The labs work as chemical sleuths using a scientific sorter technique called chromatography to catch the drugs. Chemists can break down a mixture into its parts based on their molecular weight, acidity, or tendency to dissolve in water. They run a sample over a column packed with a material, such as silica, a finely crushed glass that interacts with the mixture to separate it. Molecules identify themselves by the time they take to pass through the column. Technicians then find the mass of each molecule. Together, these two measurements serve as a fingerprint for a drug.
Sensitive testing can tell the difference between testosterone made synthetically or in the body by looking at carbon. Different carbon molecules can have different molecular weights. Although most of the carbon in our body is in the form of carbon twelve, testosterone has a specific ratio of carbon twelve to carbon thirteen. Synthetic testosterone, however, is poor in carbon thirteen. That’s how they could find the small amounts of synthetic testosterone in Landis’ urine.
Chemists test for erythropoietin differently because it’s a large protein. With a high molecular weight (30,000 compared to 400 for a steroid), it’s too big to run on a column. Technicians suspend a sample in a gel and run it under an electrical field. The erythropoietin molecule will migrate based on its weight, giving itself up, in a sense, to the tester.
In the fight against drug doping, science can fall short. For example scientists have not yet developed a test to detect illegal levels of human growth hormone. Made naturally by the pituitary gland, athletes inject the steroid to build muscle. Also some athletes find a way to beat the system. Because they are not tested every day, there might be the right window of opportunity where a drug won’t show up.
The fight against doping isn’t close to being over. A whole industry revolves around it, working to make new tests and to close some of the loopholes.