Evaluation of immunoassays for cannabinoids in urine
A comparison was made of several cannabinoid urine assays. Two hundred randomly selected urine specimens were initially screened by two enzyme immunoassays (EMIT-st and EMIT-d.a.u.) and a radioimmunoassay (Abuscreen RIA). Selected specimens found positive by any of these methods were further analyzed by gas-liquid chromatography with flame ionization detection (GLC/FID), gas chromatography/mass spectrometry (GC/MS), and an experimental RIA from Research Triangle Institute (RTI RIA). The GLC/FID method gave confirmations in 69 to 92% of the samples, depending on the method used and the cut-off employed. GC/MS confirmed 98% of the EMIT and RIA positives using a low cut-off (20 ng/mL). All RIA positives at 100 ng/mL were confirmed by GC/MS. There was complete agreement between the RTI RIA and the EMIT assays, but not with the Abuscreen RIA at the 100 ng/mL cut-off. The study illustrates that care must be exercised in establishing assay cut-offs and the designation of false positive results.
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Related Subject Headings
- Analytical Chemistry
- 3401 Analytical chemistry
- 3214 Pharmacology and pharmaceutical sciences
- 1115 Pharmacology and Pharmaceutical Sciences
- 0301 Analytical Chemistry
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Analytical Chemistry
- 3401 Analytical chemistry
- 3214 Pharmacology and pharmaceutical sciences
- 1115 Pharmacology and Pharmaceutical Sciences
- 0301 Analytical Chemistry