Here is my experience with a Labcorp pre employment 10 panel drug screen (urine analysis) from May 2010.
When I got the job offer, my new employer said I would have to pass a drug test to begin work. When I found this out I decided to stopped smoking. Prior to this, I had basically smoked the high-grade everyday for the past several years. I was kinda trippin b/c I didn't know when the test would be. About a week later my employer called and said he had sent me a chain of custody form for the piss test. When I got it, I noticed it said LabCorp 10 panel drug test and it had some medical number. So I did some research on this forum about the different ways to pass the test and decided dilution would be the best choice for me.
Fortunately I was able to delay the day of the test and waited for exactly 3 weeks had gone since taking my last toke to do the test. During this time I was exercising and trying always to keep my heart rate up. From what I had read, exercising increases the rate at which your body expels thc metabolites - albeit not very much but at least more than normal. About 4 days before the test I started taking creatine supplements that I bought from a nutrition store.
On test day I drank a couple glasses of water and a red 32 gatorade (I like the red flavor). I also took two multi vitamin pills (watch out for multi-vitamin pills as they can make you feel like vomiting - take with bread at least). When I was peeing frequently I went to the Labcorp, sipping on another red gatorade on the way. I stopped at a BK bathroom and made sure my piss looked yellow before going to the test.
When I got to the Labcorp at about 14:15 there was nobody there. I filled out some form and the lab tech told me to empty my pockets for her. She then gave me a cup and showed me to the bathroom. The toilet had blue water and I couldn't flush it. The sink water was off limits. I filled up the cup without voiding a little first - just let it flow. I gave the cup to the pee-lady and bailed.
Two days later my employer called and said I passed. Phew! After a year of being unemployed or forced to work for s--t wages, I was pretty excited to finally get a decent job. I felt lucky b/c I was able to buy some time before the test and I know this is not always the case.
In retrospect, it would have been pretty easy to sub at the Labcorp I went to. What ever method you choose, make sure you have as much info about the type of test youre going to take as possible. Do your homework and practice your plan a couple of times before the test. Also f--k the US laws for not protecting Americans from employer drug testing.
Thanks to all those who before me who shared their knowledge and experiences. When we work together there is no drug test that can accurately measure how high we really are.