Usefulness of Sweat Testing for the Detection of MDMA after a Single-Dose Administration*

After a single 100-mg dose of MDMA, the drug appears in sweat within 1.5 hours and peaks at 24 hours, but the amount varies up to 30-fold between individuals, ranging from 3.2 to 1326.1 ng per patch. Only traces of the metabolite MDA are detected. An onsite sweat strip test is positive at 1.5 hours, though 18% false-negative results occur in the first 6 hours. Sweat patch and onsite strip testing offer noninvasive ways to monitor MDMA use.

Study at a glance

Abstract

Nine healthy male subjects and recreational users of 3,4-methylenedioxymethamphetamine (MDMA) participated in a study aimed to assess the usefulness of sweat testing for the detection of MDMA after a single 100-mg dose. Sweat was collected for up to 24 h with the PharmChek sweat patches from which drugs were eluted and then analyzed by immunoassay and gas chromatography-mass spectrometry using deuterated internal standards. The usefulness of a rapid onsite test, the Drugwipe immunochemical strip test, was also assessed. In the sweat patches, MDMA was detected as early as 1.5 h after consumption and peaked at 24 h. Intersubject variability was large; peak MDMA concentrations for the same dose varied in magnitude 30-fold. MDMA concentrations ranged between 3.2 and 1326.1 ng/patch. Only traces of the minor metabolite 3,4-methylenedioxyamphetamine were detected. In all subjects, the onsite test with the Drugwipe was positive at 1.5 h (peak time of MDMA plasma concentration). However, few false-negative results (18%) appeared in the first 6 h after administration. Both sweat patch testing and the onsite sweat strip test may find useful application for noninvasive monitoring of MDMA abuse in sweat.