Steroid testing and false positives

In light of today’s baseball HoF voting results (and how a 500 HR/3000 hit guy just got dropped off of the ballot primarily because he failed such a test), I’d appreciate the straight dope on false positives on such tests.

This article claims that they are essentially impossible, but other sources indicate that it could be 5-15%, or even higher. My inquiry is two-pronged: how accurate is the test(s) in general from a chemical viewpoint, and what do the math/statistics say about false positives? My impression from the math side of things is that false positives are much more common than you might think.

It just depends on the specific substance tested for. I have read about basic problems with tests that look for athletes taking testosterone : the test tries to measure a ratio between 2 metabolites that can go out of balance if they are injecting additional testosterone.

Some substances are extremely difficult to detect because of their nature (such as abusing human growth hormone injections : this is a delicate protein product your body produces normally as it is).

Also, a drug panel for an athlete involves a lot more tests. If each one has a small false positive rate, and there are a large number of tests, the chance that an athlete is false positive for at least one test goes up considerably.

With all that said, he’s probably cheating. The financial motivations are extreme : just a few % difference can make the difference between millions of dollars in a contract and being dumped from the league.

Well I can’t connect to gizmodo right now, but 15% is ridiculous - no union or court - or pretty much anyone would agree to a test with such a high error rate. Are you getting tested after every game. If so - that means EVERYONE in baseball would test positive.

Not sure what the numbers are, but anyone claiming 15% is full of it - at best distorting stats for their own purpose.

Looks like they are using something similar to the passport program that was done in the Tour de France.

Like Habeed said - some of this stuff can’t be tested for directly - so it is going to depend on the substance and protocol - I’m sure there are numbers somewhere.

The test for something like testosterone will be very straightforward, so by splitting the sample in two you’re essentially eliminating false positives for practical purposes.
With these natural substances that are present endogenously, there’s still always going to be some amount of wriggle room for the athlete to try and bullshit their way out of it. You’re testing for an unusual ratio of compounds that are present naturally.

For a synthetic steroid, say stanozolol (winstrol), no amount of bullshitting can save the athlete. (Interesting conspiracy theory - Ben Johnson got done for Winstrol and claimed his sample was spiked by another athlete. He freely admits to being on the gear, as was every other sprinter in the Seoul 100m final, but said he never took Winstrol as it made his joints feel tight).

A false positive will be more likely for a more complicated test - say when the first EPO tests were being developed, you’re trying to distinguish subtle differences between the natural protein and the recombinant one, which I’d expect to be more challenging and more subject to errors. The UCI just placed a limit on red blood cell count in the interim, (actually still in place I believe), whilst the EPO test was developed to a reliable standard.