Open AccessEvaluation of Two Enzyme Immunoassays for the Detection of the Cocaine Metabolite Benzoylecgonine in 1,398 Urine Specimens
Author(s) -
Carney Sarah,
Wolf Carl E.,
TarnaiMoak Lisa,
Poklis Alphonse
Publication year - 2012
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/jcla.21498
Subject(s) - benzoylecgonine , urine , metabolite , immunoassay , chromatography , chemistry , gas chromatography–mass spectrometry , mass spectrometry , medicine , antibody , biochemistry , immunology
Background Benzoylecgonine ( BE ) is the primary urinary metabolite of cocaine. Two enzyme immunoassays were evaluated for the detection of BE in urine with a 300 ng/ml cutoff: the DRI ® Cocaine Metabolite Assay and Lin‐Zhi International's ( LZ ) Cocaine Metabolite Enzyme Immunoassay. Methods This study involved 1,398 urine specimens from criminal justice and pain management programs. Gas chromatography/mass spectrometry ( GC/MS ) data were obtained for presumptive positives, and for negative urine specimens yielding responses significantly above the negative control. Results Approximately 46% (644) of the specimens yielded positive results by DRI , and 47% (664) were positive by LZ . One specimen screened positive with both assays but was found to have a nondetectable BE concentration by GC/MS , indicating one false positive for each assay. Twenty‐one specimens yielding negative DRI results contained BE above 300 ng/ml, and 29 specimens yielded false negatives with the LZ assay. Therefore, the overall agreement between both immunoassays and GC/MS results was 98%. Assay sensitivity was 0.968 ( DRI ) and 0.958 ( LZ ); the selectivity for both assays was 0.999. Urine specimens containing cocaine, additional cocaine metabolites, and other drugs were also tested. No cross‐reactivity was observed. Conclusion Both the DRI and LZ assays provide a precise, reliable method for the routine detection of BE in urine. J. Clin. Lab. Anal. 26:130‐135, 2012. © 2012 Wiley Periodicals, Inc.