Have drug testing questions? Get answers from Experts
It is possible that over-the-counter medications causes false positive tests. But they will test it with chromatography & mass spectrometry to confirm it is real positive or not. If the hair test with chromatography & mass spectrometry is positive, it is true positive.
What part should I read in the site?
What is positive for your test? What over-the-counter medication did you take? Did you take prescription medications before your test?