We all know what they are looking for in the drug tests. A standard test: THC, cocaine, opiates, methamphetamines, and amphetamines. But what if you stay clean but fail a test anyway? How is that possible?

- I haven’t been smoking weed for over a month now. And back then I didn’t smoke too much. Every once in a while I get that stuff off the internet, it gets me almost half as high, but at least it’s something, you know. It is supposed to be completely legal and not show up on the test. The thing is, earlier this week I had a test and I failed. I can’t understand why.
- How often were you smoking it? Were you mixing it with regular marijuana?
- No, no, I wasn’t mixing it and only smoke once in a while, but actually, now that I think of it… the pipe that I used was dirty. I’ve had that for years and never cleaned it after I quit pot. So, I guess that’s why, ah?
- That seems to be it…

Marijuana residue does not raise toxin level in a body by much, but it is better to be safe than sorry – check yourself with a home test before going for an official one.