The current first-line defense for detecting testosterone abuse in sports is to measure the ratio of two chemicals in a spot urine test: testosterone glucuronide (TG) and epitestosterone glucuronide (EG). TG is a by-product of testosterone in the body; it increases as the amount of testosterone increases. EG is unrelated to testosterone metabolism, and serves as a reference point in testing.
In doping tests, any ratio above four, according to the International Olympic Committee, should be considered suspicious and lead to further testing.
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).
The production of TG from testosterone, however, is primarily controlled by an enzyme (UGT2B17), which is produced by a specific gene. Common variations to this gene may give rise to wildly different testing results, even when the same dose of testosterone has been taken.
For their study, the researchers screened 145 men for the insertion (ins) or deletion (del) of this gene. Among the participants, 15 percent had no copies of the gene (del/del), 52 percent had one copy (ins/del), and 33 percent carried two copies (ins/ins).
From this group, the researchers selected 55 men (17 del/del, 24 ins/del, and 14 ins/ins) to receive a single 360 mg dose of testosterone. The men were then routinely tested over a 15-day period for the telltale signs of doping.
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.
A full 40 percent of the del/del subjects never reached the detection threshold in a standard doping test. “Nearly half of the individuals in our study who carried this genetic variation would go undetected in a regular doping test after a single 360 mg dose of testosterone,” said Dr. Schulze.
If you were born without the genetics to beat a drug test, then you have a fair chance of failing the drug test even if you are innocent.
Of equal interest, 14 percent of the ins/ins subjects were naturally over the detection threshold even without receiving a testosterone injection. Based on an earlier study, the researchers estimate that this would give a false-positive rate of 9 percent in a random population of young men. “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.”
Maybe athletes will start taking advantage of relatively inexpensive personal genome services to learn things like the likelihood of side effects from anabolic steroids and the likelihood of being able to get away with using banned substances?
Most importantly, this study provides solid evidence that innocent athletes can be falsely accused when relying on the T:E ratio test.
A few other things learned:
A level playing field doesn’t exist even at the genotypic level even when it comes to the ability escape doping detection
Could there be a rogue chemist who discovered a pharmaceutical drug that can block the UGT2B17 enzyme?
Certain “ethnic populations” are more/less likely to get caught when using banned substances like testosterone (e.g. East Asians and Swedish Caucasians).
It's not for a job trust me I know my job doesn't test for the juice its for a competition
hey bro do some reading before you start sayin i'm COMPLETELY WRONG about something. imo, i've never been completely wrong about anything except a woman. lol
this clearly show almost 1 out of 2 passed the test taking either 250mg or 500mg of test cyp per week.
A 21-day T sampling period was appropriate to determine the t1/2 of exogenous T because gonadotropin-releasing-hormone stimulation tests indicated that the hypothalamic–pituitary–testicu lar axes of the subjects did not regain sufficient sensitivity to stimulate release of T until 4–6 weeks after discontinuation of the TC injections. The individual elimination half-life data are presented in Table 1⇓ . There was no difference in half-life values between the weekly TC doses of 250 and 500 mg (Mann–Whitney U = 25.0, P = 0.37). The overall mean ± SD elimination half-life for free T in serum after administration of TC was 6.6 ± 2.3 days. Based on these data, an 11-day t1/2 would be 2 SD from the mean. Given that 97% of the exogenous T was excreted in 5 half-lives (i.e., 11-day half-life × 5 half-lives = 55 days, or 8 weeks) and that pituitary sensitivity to gonadotropin-releasing hormone returned within 4–6 weeks of the last TC injection, subjects were assumed to have ceased taking (“be off”) exogenous T by the time of the urine drug screen performed 9 weeks after the last TC injection.
The AS urine drug screen findings indicated that the urinary T/E ratio cutoff of ≥6, the traditional laboratory marker to determine the use of exogenous T and used as such by the National Collegiate Athletic Association and the IOC, although quite specific for determining nonuse of T, is not a sensitive indicator for detecting illicit T usage. Table 2⇓ illustrates this. Although the T/E ratio of >6 had 96% specificity in identifying our subjects as being off steroids by 9 weeks after their last dose, it was correct only 54% of the time for identifying our subjects as being on steroids during the 14 weeks of TC injections and in the 9 subsequent weeks when they received sham injections. As a practical matter, these data suggest that one of every two subjects using injectable TC will, both during injection periods and for 9 weeks afterwards, give a false-negative urine drug screen. Receiver operating characteristic (ROC) analysis of these data (12) identified a urinary T/E ratio of ≥1.2 as the cutoff value that provided optimum sensitivity and specificity for indicating use or nonuse of T. Resorting the data in Table 2⇓ illustrates that use of a T/E ratio of ≥1.2 for a T-positive urine improves the sensitivity to 83% and the specificity decreases only somewhat, to 77%.