I too must do a urine test for a job that I actually have but have yet to start. I stopped smoking about 2.5 weeks ago, I'm 350lbs and smoked once a day usually right before bed for about 3 months straight. After 1 week of abstinence I took an "at home" brand name THC test and it said negative.

It states in the handbook that even the most faint mark on the test line means negative, buuuuut... it also says in the handbook that an overabundance of THC can override the test and generate a false negative meaning that THC is present but the test cannot handle it and gets confused thus producing a false negative. I took a second test last week with the same results.

I then chose to have a professional lab, Quest Diagnostics, screen my urine for THC at my own expense and my test came back positive for THC. This leads me to believe that this test might be fine for mommy checking to see if little tommy is hitting the bong, but I wouldn't trust it as far as determining if you are safe to pee for work.

My first day of work is monday and I might try to dilute, but if they use the same kind of off the shelf test as I did, maybe I'll get lucky and the person administering the test will be none the wiser.