Quote Originally Posted by JamesCole770
Is it true that vitamin B2 can cause a false positive (I have seen a few sources that claim that it can)?
A "false-positive" for THC?

If such claims were actually true, then persons who, in routine, utilize a high Riboflavin breakfast diet would be hit with false-positives.


Are false positives a concern if a follow up lab test on the sample (i understand that preliminary positive results are generally followed by lab tests) is included?
False-positives are eliminated when the urine sample undergoes the confirmation GC/MS. The GC/MS would distinguish between illicit and non-illicit substances.


Also, can the lab detect high amounts of B2 and conclude that the donor was trying to cheat?
Nope. The labs determine an overly-diluted sample by testing for low levels of creatinine and specific gravity. Riboflavin (B2) is not tested for on a urine sample collected for a drug test. There are no upper/lower level standards established for Riboflavin.