False positive urine amphetamine immunoassay due to solriamfetol

Solriamfetol is a schedule IV-controlled substance used to treat excessive daytime sleepiness resulting from narcolepsy or obstructive sleep apnea. We present a patient prescribed solriamfetol who tested positive for amphetamines on a routine urinary toxicology screen despite patient denial of illicit drug use, raising the possibility of a false positive amphetamine screen. Spiking studies were performed on negative urine, and different concentrations of solriamfetol drug on 2 different amphetamine assays: the commonly used Beckman Emit® II Plus Amphetamines Assay, and the Citrine™ Triple Quad™ MS/MS Systems. The Beckman yielded positive results for amphetamines at solriamfetol concentrations of 200 μg/mL and 2000 μg/mL and negative results at 0.2 μg/mL and 2 μg/mL. However, the Citrine™ Triple Quad™ MS/MS Systems was negative at all concentrations. The Beckman Emit® II Plus Amphetamine Assay gave false positive results for amphetamines due to solriamfetol drug usage, a finding of relevance to prescribers of solriamfetol.