Journal of Clinical Toxicology
Open Access
ISSN: 2161-0495
+44 1478 350008
ISSN: 2161-0495
+44 1478 350008
Andrea McGonigle, Ernest Jimenez and Leslie V. Boyer
Scientific Tracks Abstracts: J Clinic Toxicol
T he high rate of false positives in the phencyclidine (PCP) immunoassay is well known. In fact, in some institutions and patient populations, the rate of false positives actually outweighs the rate of true positives. This feature of the assay has even caused it to be abandoned by some institutions. However, this same feature makes the assay attractive for use as the starting point in an algorithm for detection of PCP, the designer drug methylenedioxypyrovalerone (MDPV) and other common PCP cross-reactors. To our knowledge, this use of the PCP immunoassay has yet to be reported. We present three cases in which the PCP immunoassay was useful despite the high false positive rate. In each case, urine samples were initially analyzed by PCP immunoassay and positive results were further investigated by thin-layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). Mass spectral data obtained were compared to known standards. All three patients demonstrated a positive PCP immunoassay result. Analysis by TLC and GC-MS demonstrated that PCP, MDPV, and diphenhydramine, were the substances accounting for the positive immunoassay results. In each case, use of the PCP immunoassay as the starting point in a screening algorithm led to the appropriate confirmatory results. In one case, it also led to the detection of the relatively new designer drug, MDPV, in the patient�s urine sample. We conclude that the PCP immunoassay, when used in conjunction with confirmatory analysis is a powerful tool for the detection of PCP and its cross-reactors, including relatively new designer drugs like MDPV
Andrea McGonigle, studied art, biology and chemistry at Arizona State University in Tempe, Arizona. She completed her M.D. at The Ohio State University College of Medicine and is currently a third year pathology resident and chief resident at the University of Arizona