What factors can cause false positive drug test results for Meth and Barbiturates?

Question by tracy s: What factors can cause false positive drug test results for Meth and Barbiturates?
I am dealing with an individual that denies illegal drug use. She continues to test positive for meth. She uses an inhaler. Her drug tests have been sent off for more through testing. What do I need to know and to look for to determain if she is testing falsely or if she is using meth?

Best answer:

Answer by sovereign_carrie
An inhaler could possibly create a false positive, depending on the brand of inhaler. I’ve read that primatine mist can cause a false methamphetamine positive due to the way the chemical is metabolized. She could also be popping other types of amphetamines, such as Adderall, instead of using “meth”. Does she have ADHD? There’s pills sold in gas stations all over the place here that have psuedoephedrine in them, which causes a false meth positive. They’re often marketed for asthma sufferers.

Taurine, from energy drinks, can cause a false positive for some narcotics. Use your judgement. If the levels are low, it could be a false positive, but if the levels are high, then I think it’s safe to assume that it’s a correct test. Some OTC painkillers can cause a false marijuana positive, but showing levels only slightly over the “Legal” limit of THC, for example.

Check here, http://www.askdocweb.com/falsepositives.html

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