If I were you I would run to the local pharmacy and purchase an at home drug test so you can test yourself before you go into to see your PO. Forget about the niacin everything I have read on this forum by informed posters is that it does not work. If you pass then dillute your urine with 40 oz. of gatorade about 1-2 hours before your appointment. Make sure you pee at least 2 times before you submit your sample. If possible use your midstream pee. If you do not pass the at home test, read the dillution sticky and follow it exactly, skip the aspirin, that part is outdated, and sub gatorade for water. You do not have a lot of time to load up on creatine so eat as much red meat, chicken and/or fish as you can today.