The testosterone:epitestosterone ratio (T:E ratio) test is a commonly used test designed to catch athletes who artificially manipulate their testosterone levels (usually with exogenous testosterone). The T:E ratio is routinely used in doping protocols around the world at all levels of sport.
Unfortunately, the T:E ratio is not very effective. This has been common knowledge among drug tested athletes for some time. Dan Duchaine first alerted athletes decades ago with Victor Conte concurring more recently. Anti-doping experts such as Charles Yesalis and Don Catlin have reluctantly acknowledged that this is true.
It is not very reliable. It is flawed. The T:E ratio test results in a lot of false negatives (athletes use testosterone but don’t get caught) as well as false positives (innocent athletes test positive for steroid use).
It appears that certain genotypes are more likely to have false negatives (athletes use testosterone but don’t get caught)and other genotypes are more likely to have false positives (innocent athletes test positive for steroid use) (Doping Test in Sports Confounded by Common Genetic Trait, March 21).
If you’re a genetically gifted athlete (i.e. you lack the gene that produces the enzyme UGT2B17), you can take an whopping injection of at least 360 milligrams of testosterone without getting caught by the testosterone:epitestosterone ratio test (T:E ratio). This testosterone loophole in drug testing has been known by athletes for decades (anecdotally). It is nice to have solid scientific evidence to confirm it.
The 360 mg corresponds to a 500 mg intramuscular injection of testosterone enanthate. Yes, many athletes can take this quantity of the anabolic-androgenic steroid testosterone and still pass current WADA doping controls.
The T:E ratio test discriminates based on the ethnicity of the athlete subjected to the doping protocol. This little bit of information is impossible to overlook.
So, which ethnic groups are most likely to have false negatives on the T:E ratio test?
The latest study suggests as many as 40% of athletes with UGT2B17 homozygous deletion/deletion genotype can take at least 500 mg of testosterone enanthate and still maintain a 4:1 T:E ratio. The following lists various ethnic groups with the estimated percentage that possess the “doping friendly” genotype (data extracted from here and here).
- 78.0% – Mulatto (Brazilian)
- 66.7% – Eastern Asian (Korean)
- 57.3% – Cape Colored (Cape Town, South Africa)
- 37.6% – Mexican Mestizo
- 30.4% – Asian Pacific (Southeast Asian/Southern Chinese, Asian Indian, Japanese)
- 29.1% – Black (African Americans, African Blacks, South/Central American Blacks)
- 9.3% – White Caucasian (Swedish)
- 3.5% – White Caucasian (primarily European)
Yes, athletes with UGT2B17 homozygous deletion/deletion genotype are much more likely to pass a doping test if they choose to cheat (false negative). And yes, certain ethnic groups are much more likely to possess this genotype.
What should WADA do about this? Is this a problem for professional sports or high school districts that routinely use the T:E ratio test?