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Publications (2)4.21 Total impact

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    ABSTRACT: The object of this study was to evaluate the suitability of the Neogen Corp. microtiter plate enzyme-linked immunoassays (ELISA) for the screening of postmortem blood for amphetamine and methamphetamine and to choose the more appropriate assay for screening. Forty-seven postmortem whole blood specimens were obtained from drug-involved deaths, which had been screened and confirmed positive for methamphetamine and/or amphetamine. Eighty-five negative specimens were obtained from non-amphetamines-involved deaths, 17 of which involved decomposition. Specimens were tested using the Neogen Amphetamine Ultra and Neogen Methamphetamine/MDMA microtiter plate ELISA assays. No matrix effects were found for whole blood in these assays, and a dilution of 1:5 was chosen to facilitate pipetting and to bring the IC50 of the microtiter plate ELISA assay within the range of amphetamines concentrations encountered in medical examiner specimens. True positives, true negatives, false positives, and false negatives were determined relative to gas chromatography-mass spectrometry (GC-MS) and graphed for the ELISA. From these graphs and the receiver operating curves (ROC), the optimal cut-off for the Neogen Methamphetamine/MDMA ELISA was 50 ng/mL methamphetamine equivalents and the optimum cut-off for the Neogen Amphetamine Ultra ELISA was 100 ng/mL amphetamine equivalents. The Neogen Methamphetamine ELISA had a sensitivity of 93.6% +/- 3.5% and a specificity of 77.6% +/- 4.5% versus GC-MS at the cut-off of 50-ng/mL methamphetamine equivalents. The Neogen Amphetamine Ultra ELISA had a sensitivity of 95.7% +/- 3.0% and a specificity of 72.9% +/- 5.2% versus GC-MS at the 100-ng/mL amphetamine equivalents cut-off. The areas under the ROCs were equivalent for the two ELISA assays.
    Journal of analytical toxicology 11/2002; 26(7):513-8. · 2.11 Impact Factor
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    ABSTRACT: The object of this study was to evaluate the suitability of the Neogen Corp. microtiter plate enzyme-linked immunoassays (ELISA) for opiates and benzodiazepines for screening of postmortem blood. Ninety postmortem whole blood specimens were obtained from drug-involved deaths which had been screened and confirmed positive for opiates and/or benzodiazepines. Forty negative specimens were obtained from non-opiate-involved deaths. Specimens were tested using the Neogen Opiates Group and Neogen Benzodiazepines Group microtiter plate ELISA assays. No matrix effects were found for whole blood in these assays and a dilution of 1:5 was chosen to facilitate pipetting and to bring the IC50 of the microtiter plate ELISA assay within the range of opiates and benzodiazepines encountered in medical examiner specimens. True positive, true negatives, false positives, and false negatives were determined and graphed for the ELISA results against gas chromatography-mass spectrometry (GC-MS), gas chromatography-nitrogen-phosphorus detection and case histories. From these graphs and the ROC curves, the optimal cut-off for the Neogen Opiates Group ELISA was found to be between 20 and 50 ng/mL morphine equivalents and the optimum cut-off for the Neogen Benzodiazepines Group ELISA was between 20 and 50 ng/mL temazepam equivalents. The Neogen Opiates Group ELISA had a sensitivity of 95.2% +/- 2.7% and a specificity of 92.2% +/- 3.4% versus GC-MS at a cut-off of 20-ng/mL cut-off and a sensitivity of 88.8% +/- 3.9% and specificity of 96.8% +/- 2.1% versus GC-MS at a 50-ng/mL morphine equivalents cut-off. The Neogen Benzodizepines Group ELISA had a sensitivity of 100% +/- 1.3% and a specificity of 94.6% +/- 2.9% versus GC-MS (20-ng/mL temazepam equivalents cut-off) and a sensitivity of 95.8% +/- 2.5% and specificity of 98.2% +/- 1.8% versus GC-MS at a 50-ng/mL cut-off.
    Journal of analytical toxicology 11/2002; 26(7):504-12. · 2.11 Impact Factor