Quick answer
A positive screen is presumptive, not final. It is only reported as positive after confirmation by GC-MS or LC-MS/MS at a lower cutoff.
In detail
A screening immunoassay flags a sample when a drug or metabolite is at or above its cutoff. That screen result is presumptive. Before a result is reported as positive, the laboratory confirms it using gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) at a lower, more specific cutoff. A non-negative result is then reviewed by a Medical Review Officer (MRO), who gives the donor the chance to document a legitimate prescription or a medical explanation. Only after that review is a result verified as positive. A positive result on a screening device used at home is not confirmation and should be followed up with a laboratory test.
Frequently asked questions
Is a positive drug test result final?
A positive screen is presumptive, not final. It is only reported as positive after confirmation by GC-MS or LC-MS/MS at a lower cutoff.
What should I do next?
If you have a legitimate prescription or medical explanation, declare it through the Medical Review Officer. Follow the program's instructions for any recollection or retest.
Is this medical or legal advice?
No. This is general educational information about how drug testing works, not medical or legal advice. Consult a qualified professional about your situation.
Related
All result types · Detection chart · Test types · False positives