What is a false positive for a drug test? A false positive is a drug test that is returned positive because another compound you used set off a false positive.
It is a case of mistaken identity. For example if you eat a couple poppy seed cakes before testing, you can get a positive result for opiates.
The chances of you getting a false positive depends on the quality of the laboratory that does the testing. There seems to be about 1,200 of these labs in the United States currently testing for drugs. Less than a 100 of these meet federal standards and most of the individual states do not regulate drug test labs. The number of false positives returned range from 4% to over 50%, depending on the lab.
A concern here is that, if your company tests for drug usage, they are probably not required to use a certified drug testing lab, which means you have a greater chance of getting a false positive.
Unfortunately false positives are not always caused by other compound, human errors, such as labeling errors, inadequate training of laboratory staff and fatigue or boredom are also possible and capable of producing a false positive result.
The worst case is when a lab tech deliberately makes your clean sample positive for drugs. Which is what happen in Boston Massachusetts, a Boston crime lab chemist admitted that she altered or faked test results of drug cases assigned to her, which resulted in 1,140 possible innocent inmates convicted using tainted evidence case to be re-evaluated.
The list below shows various substances that can causes a false positive drug test result.