Accuracy of common drug screen tests

Joyce G. Schwartz, Philip R. Zollars, Anthony O. Okorodudu, Joyce J. Carnahan, Jack E. Wallace, John E. Briggs

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Forty consecutive urine specimens, obtained from patients seen in the emergency center, positive for either cocaine and/or marijuana, were analyzed using five methods of analysis. A new latex agglutination inhibition assay, Abuscreen OnTrak, (Roche Diagnostic Systems, Nutley, NJ), was compared with four other drug abuse assays: mass spectrometry, (Hewlett-Packard Co, Richardson, TX); an automated homogeneous enzyme immunoassay technique, ETS System, (Syva Co, Palo Alto, CA); a manual enzyme multiplied immunoassay technique; EMIT-st, (Syva); and a fluorescence polarization immunoassay, TDx, (Abbott Laboratories, Chicago, IL). For statistical purposes, mass spectrometry was the reference point for the presence or absence of a specific substance. All instrument sensitivities, with the exception of mass spectromatry, were set with the same "cut off" point of 100 μg/L for marijuana and 300 μg/L for cocaine and its metabolites. Efficiency in the detection of cocaine and its metabolites was 95% by all methods. Efficiency for the detection of marijuana and its metabolites ranged from 70% (Roche's OnTrak) to 90% (Syva's ETS). Simple to use, assays of minimal cost are presently available for rapid, accurate drug of abuse screening.

Original languageEnglish (US)
Pages (from-to)166-170
Number of pages5
JournalAmerican Journal of Emergency Medicine
Issue number2
StatePublished - Mar 1991
Externally publishedYes


  • Cocaine
  • cannabis
  • street drugs
  • substance abuse

ASJC Scopus subject areas

  • Emergency Medicine


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