Quote Originally Posted by butt3rcup29
This worries me. My aunt (a registered nurse with 30+ years of experience and no reason to lie) and uncle (an MD with more experience than my aunt) AND a lab tech have all three told me that Riboflavin can cause a false positive for THC, even in patients who would otherwise be clean.

Curiously, I had a lab tech who recently attended a training conference tell me that Nexium (the little purple indigestion pill) could also cause a false positive, to the point where if someone tests positive for THC after disclosing a drug history including nexium, many labs will report back inconclusive. He said when taking a history, if the patient discloses nexium, they almost expect a positive result for THC.
There are no false-positives anymore. False positives are eliminated when the sample undergoes a confirmation GC/MS. The GC/MS, being a selective and highly accurate methodology, would distinguish between THC-COOH and vitamins and/or scripted and OTC meds.

As far a Riboflavin triggering false-positives, there is no solid substantiation to this claim.
If such claims were actually true, then individuals who consume cereals rich in Riboflavin (ie, Total, Product 19, etc) as part of their breakfast diet would become victims of a false-positive.

But as I stated above, there are no false-positives anymore.