if it has been a week, it is possible. if you have any goldenseal that is the winner here. i have known people who passed a test simply by doing nothing but drinking copious amounts of water and juice the 24 hours previous. at some point the urine becomes mostly water and the mj content is very very low. i have known more than one that did that succesfully, but of course its not guaranteed. don't fast between now and the fast tho, that will trigger detox and you don't want that.