Congratulations!!! i know it really stinks to think your hard work can go down the drain for something as small as that. I get ETG testing, and i haven't had so much as cookie dough in the last 6 months. I stumbled onto all the sites about false positives a few months ago trying to find out how much the test costs. after that false amphetamine, i am taking no chances.
how long between the time you tested (initially) and you got your "positive" result? Were you able to pin anything down? Whatever you find it to be, stay away from it!!!