@article{ref1,
title="Postmortem urine immunoassay showing false-positive phencyclidine reactivity in a case of fatal tramadol overdose",
journal="American journal of forensic medicine and pathology",
year="2006",
author="Hull, Mindy J. and Griggs, David and Knoepp, Stewart M. and Smogorzewska, Agata and Nixon, Andrea and Flood, James G.",
volume="27",
number="4",
pages="359-362",
abstract="This is a report of postmortem false-positive reactivity using an enzyme-multiplied urine phencyclidine (PCP) immunoassay (EMIT II+) due to a single-agent fatal tramadol overdose. An autopsy of a 42-year-old male who died alone at home revealed no identifiable lethal anatomic abnormalities, thus leading to toxicologic analysis. Femoral blood was obtained for drug testing by high-performance liquid chromatography (HPLC) and showed a tramadol level of 14.0 mg/L, 2 orders of magnitude greater than the therapeutic range (0.1 to 0.3 mg/L). Urine was also obtained and EMIT II+ immunoassay revealed positivity for PCP at 88 mAU/min. However, confirmatory testing by HPLC failed to identify PCP in either the urine or serum. To verify the suspicion that this was a false-positive PCP result, stock solutions of tramadol and its major metabolite (O-desmethyltramadol) at concentrations of 100 mg/L in 10% methanol/H2O were compared with a blank solution (10% methanol/H2O) for EMIT II+ PCP reactivity and demonstrated reactivities of 44 mAU/min and 27 mAU/min, respectively. While these individual results were below the cutoff reactivity for a positive EMIT II+ PCP result (ca. 85 mAU/min), they were much more reactive than the blank calibrator (set at 0 mAU/min). Therefore, we conclude that the immunoreactivity of tramadol and its metabolites in aggregate is responsible for the PCP immunoassay interference and false-positive result.<p /><p>Language: en</p>",
language="en",
issn="0195-7910",
doi="10.1097/01.paf.0000233534.59330.c2",
url="http://dx.doi.org/10.1097/01.paf.0000233534.59330.c2"
}