7/25/2012: (DAY 36) I used mdlabtests.com to have my own personal drug test performed at Labcorp, and I submitted a sample to them today. I went over the substitution routine in my head while I was in the bathroom and thought to myself that it would be pretty easy to sub if I had to (I didn't feel rushed, there should be plenty of time to get it right if you practiced). My temp read 94F on the temp strip when I walked out of the bathroom (that's where the green dot was at). I'll get those results back 24-48 hours and I'm sure I'll be negative. My wife thinks I've gone completely insane going though all this, but better safe than sorry. Also got an email from work today saying my background check passed and I can schedule my u/a now. I'm going to ignore that email and push this as far as I can for good measure.