Piecing Things Together

Back in October 2006, trying to get to my dad’s house before he passed away, I was stuck on the tarmac in Atlanta, cursing the airshow in Washington, DC (my destination) that was delaying my departure. Time was short. Very short. And the two-hour delay was maddening. As I sat on the plane waiting for it to get in the air and get me to DC, I needed a distraction.

To get my mind of the never-ending wait, and the consequences of arriving late, I read some scientific articles related to doping. One of the articles, “Evaluation of Testosterone/Epitestosterone Ratio Influential Factors as Determined in Doping Analysis” from the Journal of Analytical Toxicology’s March 2000 issue especially caught my attention, as it offers some very interesting background on the T/E ratio that has been used as an indication of doping for more than a quarter century. I discussed the article in this post from way back when.

There’s an interesting history to the use of the T/E ratio, starting with the Moscow Olympics in 1980. Because techniques had come into use to detect the use of anabolic steroids during the mid- to late-1970s, many athletes who were doping switched to the use of testosterone, instead. The IOC suspected that many athletes in Moscow were using synthetic testosterone, but didn’t have a way to prove it. To determine whether or not an athlete was using testosterone, the IOC relied on studies that showed the vast majority of (Caucasian) individuals would have a T/E ratio at or below 6:1. In 1982, IOC-accredited anti-doping labs started testing for the T/E ratio, and anyone whose ratio exceeded 6:1 was considered guilty of doping with exogenous testosterone.

Over the years, the requirements to prove a doping case involving testosterone changed, to the point that eventually the 6:1 ratio became an indication to gather more data, in order to rule out naturally high ratios and/or high ratios due to some illness or other pathology. The data to prove a positive case could come from previous tests, various endocrinological investigations or tests, or unannounced testing over a period of several months (or more).

In more recent years, the T/E ratio has been used as a screening test and when an athlete exceeded the proscribed ratio (subsequently reduced to 4:1 in 2005), carbon isotope ratio testing is conducted in order to determine whether the testosterone in the athlete’s system is natural or not. Interestingly, even when the article in the Journal of Analytical Toxicology was published eight years ago, there were questions about how good a test the T/E ratio was.

Back in 2000, carbon isotope ratio (also known as GC-C-IRMS or IRMS) testing was just coming into use. It’s a much more complicated type of testing, which takes more time and is more costly to perform. But it’s also said to be able to discriminate between natural (or endogenous) testosterone and the synthetic (or exogenous) variety. Along the way, the T/E ratio test morphed into the screening test that would be followed up by IRMS studies, if necessary. The question in 2000 and today is whether the T/E is even a good screening test.

The March 2000 Journal of Analytical Toxicology article notes a number of potential problems that can affect the outcome of a T/E ratio test, and notes a number of promising technologies both for screening and confirmation. Ultimately, it found that despite the test’s flaws, it was the best method of screening for testosterone doping available at the time.

Among the flaws in the test, the authors noted, were that a certain ethnic group had very low T/E ratios (0.76, or about 3:4). These individuals, even when given large doses of testosterone, would not exceed the screening level that would trigger further investigation. This pointed to a problem of false negatives. What it didn’t address, however, was how it came to be that these people had such low T/E ratios. It also didn’t address the implications of what the cause of that might mean in in terms of the test and its value.

Well, a new paper entitled “Doping Test Results Dependent on Genotype of UGT2B17, the Major Enzyme for Testosterone Glucuronidation” being published in the June issue of the Journal of Clinical Endocrinology & Metabolism offers a potential answer. The paper suggests that there is a genetic trait that can undermine the effectiveness of the T/E ratio as a screening test. According to the press release (available over at Trust But Verify):

“Genetic factors may play an important role in the accuracy and sensitivity of testosterone doping tests,” said Jenny J. Schulze, Ph.D, of the Karolinska University Hospital in Stockholm, and lead author of the JCEM study. “This is of interest not only for combating androgen doping in sports, but also for detecting and preventing androgen abuse in society.”

Here’s the low-down, there is a set of genetic traits that, when an individual inherits one version can cause a 40% false negative rate, and when an individual inherits a different variant can cause a 14% false positive rate. Now, for the false positives, the IRMS test (when performed and interpreted correctly) is very likely to determine that a false positive has occurred. But, as the press release posted at TBV notes:

“False positive results are not only of concern for the legal rights of the sportsman,” said Dr. Schulze, “they also yield extra workload for the doping laboratories.”

So, one thing to do would be to find a way to eliminate false positives, in order to eliminate extra work and expense for the anti-doping labs. But what about the people who were false negatives? They, like all the other participants in the study, were given 360 milligram doses of testosterone, and still came up negative on the T/E screening test. In the case of false positives, if you have a follow-up test that can weed those results out (and if the results remain confidential unless an anti-doping case is pressed against an athlete — which is a big if in some places) at least no harm is done to anyone.

Athletes avoiding detection, however, do harm others — at least in the sense that they are able to cheat and get away with it, which may influence others to cheat, too. So we need to be equally or more concerned with those who manage to evade detection as with those who come up as false positives.

One common refrain is that a large number of athletes who are cheating are somehow evading detection. It’s a hard proposition to prove in a quantifiable way, because so few who have done so have ever admitted publicly that they beat the system. How many athletes have come forward voluntarily to say, “Yeah, I beat the vampires”? In Marion Jones’ case, she wouldn’t have admitted anything were it not for a certain check fraud scam of former boyfriend Tim Montgomery that came back to haunt her, too.

For a screening test to be effective, the percentage of false negatives has to remain low. Otherwise, it’s pretty well worthless. With a large number of false negatives, lots of people could evade detection. In addition, there is no additional follow-up testing that is done to see about false negatives, so once an athlete has escaped detection, he or she is out of the woods — at least until the next test. Now, however, there is evidence that some people could, in theory, evade detection by the current T/E screening tests due to the luck of who their parents were.

Sounds an awful lot like the T/E screening test with a one-size fits all threshold level is not “fit for purpose,” and that a new approach is needed. As the authors of this new study note:

Ideally, the researchers suggest that, depending on the athlete’s genotype, there should be different cut-off levels for doping tests.

Additionally, back in 2000, some other types of screening tests were already on the drawing board. It might behoove those in the anti-doping community to seriously consider changing the current protocol to be based on an athlete’s variant of the genetic trait, and also to investigate whether the techniques proposed at back in 2000 also be better equipped to discern who might or might not be cheating.

Of course, basing T/E test results on each athlete’s variant of a particular genetic trait also means knowing what variant each athlete has. And that gets into the issue of genetic and DNA testing, which raises even more issues. The solution offered by the Karolinska Institute’s researchers is intriguing. I’ll be looking forward to reading the full paper when it comes out in June. The biggest pitfall to this approach is whether or not athletes will be willing to allow such DNA or genetic testing. I suspect in some sports they will, while in other sports there will be some strong resistance to providing such samples and data.

The Karolinska researchers’ discovery is a development to keep your eyes on.