ISSN: 0022-1198
CODEN: JFSCA
Page Count: 5

CEDIA for Screening Drugs of Abuse in Urine and the Effect of Adulterants
Wu, AHB
Director, and Assistant Supervisor, Toxicology Laboratory, Hartford Hospital, CT

Forte, E
Director, and Assistant Supervisor, Toxicology Laboratory, Hartford Hospital, CT

Casella, G
Graduate Student, University of Connecticut, CT

Hemphill, G
Director of Occupational Toxicology, Medtox Laboratories, MN

Schanzenbach, H
Clinical Trials Coordinator, Microgenics Corporation, CA

Sun, K
Director of Toxicology, Methodist Hospital of Indiana Inc., IN

Foery, R
Vice President and Technical Director, MedExpress Laboratories, TN

(Received 7 September 1994; accepted 8 December 1994)

Abstract

The performance of the Microgenics CEDIA® DAU assays for screening amphetamines, barbiturates, benzodiazepines, cocaine, opiates, phencylidine (PC), and tetrahydrocannabinol (THC) was evaluated on the Boehringer Mannheim/Hitachi 717 in urine. Limits of detection ranged from 0.6 ng/mL for PCP, to 34.1 ng/mL for benzodiazepines. The average within run and total precision for these assays ranged from 1.3 to 7.3% for controls at cutoff concentrations, and control values at −25% and +25% of cutoffs. The rate separations by CEDIA between the negative and cutoff calibrators for all drugs were greater than corresponding EMIT II (Syva Co.) assays. The relative sensitivity and specificity of CEDIA as compared to EMIT II were 95.6 and 98.8%, respectively, on 13,535 urine samples. All positive samples, and those samples producing discordant results between the assays were confirmed by quantitative gas chromatography/mass spectrometry (GC/MS). Using SAMHSA cutoff limits (and including barbiturates and benzodiazepines at 300 ng/mL), the relative sensitivity and specificity of CEDIA vs. EMIT II were 96.7 and 98.8%, respectively. The overall sensitivity of CEDIA vs. GC/MS was 98.9% with 179 false positives, as compared to 96.2% with 189 false positives for EMIT II vs. GC/MS. The effect of adulterants added to urine to potentially invalidate screening results was also tested. CEDIA produced strong interferences for most drug assays in the presence of glutaraldehyde, detergent, and high concentrations of bleach and Drano. Minimal or selective interferences were seen with golden seal tea lemon juice, Visine, and low concentrations of bleach and Drano. Essentially no interference was observed with bicarbonate, sodium chloride, and vinegar.

Keywords:
toxicology, enzyme immunoassay, gas chromatography/mass spectrometry, workplace drug testing, adulteration

Paper ID: JFS13836J
DOI: 10.1520/JFS13836J
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