substitution or abstaining, when u pee at a dr. they usually have temp strips so they don,t have to follow u in, get a clean sample in leakproof container<condom has worked for me at probation back in the day> drop it in a cup of coffee for the ride down, slip into band of underwear in parking lot so it is next to your skin, u can flush the evidence, if some nazi wants to follow u in, just explain that u have to sit to pee cause your tummy is upset and don't want to soil your pants, now send me some of that money you were wasting on bogus majik kleeen!!!