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Leclercq M, Soichot M, Delhotal-Landes B, Bourgogne E, Gourlain H, Mégarbane B, Labat L. False positive amphetamines and 3,4-methylenedioxymethamphetamine immunoassays in the presence of metoprolol—two cases reported in clinical toxicology. J Anal Toxicol 2019; 44:200-205. [DOI: 10.1093/jat/bkz051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/17/2019] [Accepted: 05/27/2019] [Indexed: 11/12/2022] Open
Abstract
Abstract
Amphetamines, frequently used recreational drugs with high risk of toxicity, are commonly included in urine drug screens. This screening is based on enzyme immunoassay, which is a quick and easy-to-perform technique, but may lack specificity resulting from cross-reactivity with other compounds, causing false positive results. We present two cases of presumed false positive MULTIGENT® amphetamine/methamphetamine and MULTIGENT® ecstasy (Abbott®) immunoassays with the beta-blocker metoprolol. Both metoprolol-poisoned patients presented positive urine screening despite no history of drug abuse. No confirmation for amphetamine molecular structures was found with gas chromatography–mass spectrometry. The cross-reactivity was further investigated by doping urine samples with metoprolol and its two major phase-I metabolites. Metoprolol showed positive results for both amphetamine and MDMA tests at low concentrations (200 and 150 μg/mL, respectively). Metoprolol metabolites cross-reacted with the amphetamines immunoassay only, but at higher concentrations (i.e., 2000 μg/mL for α-hydroxymetoprolol and 750 μg/mL for O-demethylmetoprolol). In conclusion, false positive results in amphetamines and MDMA immunoassays are possible in the presence of metoprolol. Toxicologists should be aware of frequent analytical interferences with immunoassays and a detailed medication history should be taken into consideration for interpretation. In vitro investigation of suspected cross-reactivity should include not only the parent drug but also its related metabolites.
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Affiliation(s)
- Marion Leclercq
- Service de Toxicologie, Hôpital Lariboisière, AP-HP, 2 Rue Ambroise Paré, Paris 75010, France
| | - Marion Soichot
- Service de Toxicologie, Hôpital Lariboisière, AP-HP, 2 Rue Ambroise Paré, Paris 75010, France
| | | | - Emmanuel Bourgogne
- Service de Toxicologie, Hôpital Lariboisière, AP-HP, 2 Rue Ambroise Paré, Paris 75010, France
| | - Hervé Gourlain
- Service de Toxicologie, Hôpital Lariboisière, AP-HP, 2 Rue Ambroise Paré, Paris 75010, France
| | - Bruno Mégarbane
- Service de Réanimation Médicale et Toxicologique, Hôpital Lariboisière, AP-HP, 2 Rue Ambroise Paré, Paris 75010, France
- INSERM UMRS-1144, Universités Paris-Descartes et Paris-Diderot, 4 Avenue de l’Observatoire, Paris 75006, France
| | - Laurence Labat
- Service de Toxicologie, Hôpital Lariboisière, AP-HP, 2 Rue Ambroise Paré, Paris 75010, France
- INSERM UMRS-1144, Universités Paris-Descartes et Paris-Diderot, 4 Avenue de l’Observatoire, Paris 75006, France
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