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Published:
Journal of Analytical Toxicology,
ISSN 0146-4760,
Volume 25, Number 7, October, pp. 559-564
A Comparison of Roche Kinetic Interaction of Microparticles
in Solution (KIMS®) Assay for Cannabinoids and GC–MS Analysis for 11-nor-9-Carboxy-D9-Tetrahydrocannabinol
Timothy P. Lyons[1], Catherine K. Okano[1], Judith
A. Kuhnle[1], Mark R. Bruins[1], William D. Darwin[2], Eric T. Moolchan[2],
and Marilyn A. Huestis[2]
[1]Forensic Toxicology Drug Testing Laboratory, Tripler Army Medical Center,
Honolulu, Hawaii 96859 and [2]Chemistry and Drug Metabolism, IRP, NIDA, NIH,
5500 Nathan Shock Drive, Baltimore, Maryland 21224
In this study, we investigated the effectiveness of the Roche
Kinetic Interaction of Microparticles in Solution (KIMS) screening assay for
cannabinoid metabolites. Urine specimens (N = 1689) were collected during elimination
of cannabinoids from 25 subjects with a history of marijuana use. Specimens
were analyzed concurrently for cannabinoid metabolites by a customized Department
of Defense (DOD) cannabinoid KIMS kit (50-ng/mL cutoff) and for 11-nor-9-carboxy-Ð9-tetrahydrocannabinol
(THC-COOH) by GC–MS (15-ng/mL cutoff). As compared to GC–MS results,
the sensitivity, specificity, and efficiency of the KIMS assay were 69.7%, 99.8%,
and 88.6%, respectively. Many of the false-negative results had GC–MS concentrations
between 15 and 26 ng/mL (N = 151). The cannabinoid screening results for the
DOD samples tested by the laboratory during the same 8-month period were also
evaluated. The linear regression analyses of GC–MS results in the 15–50
ng/mL range and KIMS data resulted in regression coefficients of 0.689 for the
research specimens and 0.546 for DOD specimens. The results suggest that the
KIMS cannabinoid screening assay is deficient in detecting positives around
the cutoff (15–25 ng/mL THC-COOH). This limitation of the KIMS cannabinoid
screening method compromises the identification of true positive specimens,
therefore reducing the effectiveness of the assay. The success of the DOD program
is dependent on sensitive and specific screening assays; the high prevalence
of false-negative cannabinoid results compromises the program’s primary
objective of drug deterrence.
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