You druggies are idiots.
The best way to pass a drug test is too start loading up on creatine starting 3-5 days before the test. Take a lot of B-complex vitamin the day before. Then drink enough water to dilute your piss. You have to be relatively clean to pass this, but the creatine will pass the specific gravity portion of the test, the b-vitamin will keep your piss yellow when you dilute it, and diluting your piss keeps the amount of drug per ml of piss to an acceptable level to pass the drug test.