I have had a few friends that got tested for alcohol and bac water or prop will not make you fail a test. HOWEVER...if you are taking prop, you have to be careful with what is used to constitute it. I cannot remember what it actually is, but some suppliers use something to help get higher amounts of the raw materials in their oils to get a higher potency, and whatever that is can cause false positive on a test...sorry I cannot remember what that is, but figured I would share what I knew about it.