Mesc can be tested for, but it's not tested for in standard tests and even extended tests. Whether or not it will throw a false positive for amphetamines, I can't seen to find an answer for. Even if it did, request a proof test for amphetamines and it will show negative unless you've recently used true amphetamines. In any case, a proof test will add some delay between use and test, and that means more of it out of your system! Unless they're doing a hair test.. hehe