Can prescription medications cause a false positive drug test result?

Yes, certain prescription and over-the-counter medications can trigger a preliminary positive (non-negative) result on an initial drug screen. Common examples include: certain antihistamines (such as diphenhydramine/Benadryl) may trigger a positive for opiates or methadone; some decongestants (pseudoephedrine) may trigger a positive for amphetamines; prescribed benzodiazepines, opioids, or ADHD medications (amphetamine-based) may naturally show positive results. This is why all non-negative results are sent to a certified Medical Review Officer (MRO) for confirmation testing using GC/MS (Gas Chromatography/Mass Spectrometry). The MRO will contact the donor to ask about any prescription medications that could explain the result. If a valid prescription is verified, the result is typically reported as negative. Always disclose current medications to the MRO during the review process.