title: False-positive methadone urine drug screen in a patient treated with quetiapine.
abstract: We present a case of T.M. admitted to University Department of Psychiatry, Split University Hospital Center, in Croatia, because of the acute psychotic reaction (F23.9). The patient's urine tested positive for methadone without a history of methadone ingestion. Urine drug screen was performed with the COBAS Integra Methadone II test kit (kinetic interaction of microparticles in solution /KIMS/ methodology) by Roche. Drugs that have been shown to cross-react with methadone feature a tricyclic structure with a sulfur and nitrogen atom in the middle ring, which is common for both quetiapine and methadone. Therefore, it is plausible that this structural similarity between quetiapine and methadone could underlie the cross-reactivity on methadone drug screen. Besides quetiapine, a number of routinely prescribed medications have been associated with triggering false-positive urine drug screen results. Verification of the test results with a different screening test or additional analytical tests should be performed to avoid adverse consequences for the patients.
authors.affiliation: University Department of Psychiatry, Split University Hospital Center, Split, Croatia. dlasic@kbsplit.hr
authors.forename: Davor
authors.initials: D
authors.lastname: Lasić
authors.forename: Boran
authors.initials: B
authors.lastname: Uglesić
authors.forename: Marija
authors.initials: M
authors.lastname: Zuljan-Cvitanović
authors.forename: Daniela
authors.initials: D
authors.lastname: Supe-Domić
authors.forename: Lovro
authors.initials: L
authors.lastname: Uglesić
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003987:Dibenzothiazepines / Q000627:therapeutic use*; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D008691:Methadone / Q000652:urine*; D000069348:Quetiapine Fumarate; D015813:Substance Abuse Detection
chemical_list: D014150:Antipsychotic Agents; D003987:Dibenzothiazepines; D000069348:Quetiapine Fumarate; D008691:Methadone