Drug Testing Misunderstood

by blogger jgl

This case really irks me. First off, I'll be the first to admit that mistakes can be made in labs and it is entirely possible for false positives to occur. I will feel extremely bad for this guy if it turns out the lab made a mistake. However, if a mistake does occur, "proving your innocence" through shoddy forensic science is not the right path to take. Pay attention, forensic scientists! This is a classic example of an inappropriate use of forensic science to sway public opinion.

A summary of the case is as follows: Bronco's tailback Travis Henry tested positive for THC (urine). He's "proves" his innocence by taking a lie detector test and having his hair tested for drugs.

Travis Henry has convinced coach Mike Shanahan he's not a pothead. Now he'll take his case to the NFL. Shanahan said Henry passed a lie detector test and a recent hair sample taken from Henry came back negative for marijuana. "If the tests were positive, Travis would not be on our football team right now," Shanahan said. "When he went back and took the hair sample and that was negative, the lie detector test and that was negative, we'll let due process take care of itself. If Travis took a test and it was positive, after what he promised me, he wouldn't be on the football team right now."

Mainly because of his attempts to prove his innocence using *science*, his coach and TV personalities (including ESPN's Michael Wilbon and Dan LeBatard) are convinced he is likely telling the truth. I don't expect these guys to know anything about drug testing, but here are the facts:

Lie detectors DO NOT WORK.
Drug testing of hair DOES NOT WORK (for the most part).

Even if hair testing did work all the time, his hair is awfully short (grown in since the last drug test). By taking these bogus tests that scientifically prove nothing, Travis Henry has tricked educated people into jumping on his bandwagon. This demonstrates something most forensic scientists know, *the public often perceives anything scientific as infallible, but can't differentiate between "good" and "bad" science.*

If he really wanted to proclaim his innocence, then he should request that the lab retest his original sample. I don't work in a workplace drug testing lab, but don't they save a portion of samples for some length of time afterwards? Is Henry claiming his sample was mixed up with someone else's? How likely is this? Oh wait, it looks like the lab does have another sample that's already been tested according to this article.

But in a battle that has reached the federal court system, Henry is attempting to block the league from testing the so-called "B-sample" necessary to confirm the positive test, claiming that NFL officials would not allow his expert to be present for the testing of his specimen.

Something doesn't smell right. Plus, I hate to use a non-scientific fact to prove a point, but Henry has tested positive for drugs before (in 2005).