I also read that it probably wasn't just a pee test divided into 2 samples, its more comprehensive than that, and he probably failed a series of tests. The last test was likely a sophisticated blood test.
All of those tests have false positive rates, but to coincidentally get a false positive on all of them is 1 in millions lottery type of odds.
<ptp> how many emo kids does it take to change a lightbulb?
<Willy> HOW MANY?!
<ptp> none they just sit in the dark and cry