Modification of screening immunoassays to detect sub-threshold concentrations of cocaine, cannabinoids, and opiates in urine

Use for detecting maternal and neonatal drug exposures

Eyas M. Hattab, Bruce A. Goldberger, Laura M. Johannsen, Pat W. Kindland, Frances Ticino, Chris W. Chronister, Roger L. Bertholf

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Testing for drugs of abuse in urine is commonplace in emergency departments and neonatal units. However, the clinical sensitivity of immunochemical screening methods is limited by the threshold concentrations used to distinguish between positive and negative specimens. Immunochemical screening methods for cocaine metabolite (benzoylecgonine), cannabinoids, and opiates in urine were recalibrated to detect drugs at lower threshold concentrations. The precision and linearity of the signals at the modified thresholds were verified by diluting drug-positive urine specimens to concentrations below the conventional cutoff concentration and measuring the rate signals in triplicate. To assess the clinical performance of the modified methods, specimens that tested negative using the unmodified assays were re-screened at the lower threshold, and specimens that re-screened positive were submitted for gas chromatographic/mass spectrometric (GC/MS) confirmation. Reproducibility of sub-threshold measurements was comparable to the unmodified assays, and rate separations between successive dilutions were sufficient to give semi-quantitative results. Using the lower thresholds, drugs were detected in 4-5% of the subjects that had screened negative at the conventional threshold concentration. GC/MS analysis confirmed the presence of cannabinoids and cocaine metabolite in 74% and 84%, respectively, of urine specimens that re-screened positive. Morphine, codeine, hydromorphone, or hydrocodone was detected by GC/MS analysis in 31% of opiate-positive re- screens.

Original languageEnglish (US)
Pages (from-to)85-91
Number of pages7
JournalAnnals of Clinical and Laboratory Science
Volume30
Issue number1
StatePublished - Jan 2000
Externally publishedYes

Fingerprint

Opiate Alkaloids
Cannabinoids
Cocaine
Immunoassay
Screening
Gases
Mothers
Urine
Metabolites
Assays
Hydrocodone
Hydromorphone
Pharmaceutical Preparations
Codeine
Street Drugs
Morphine
Dilution
Hospital Emergency Service
Testing

Keywords

  • Benzoylecgonine
  • Cannabinoids
  • Cocaine
  • Drugs of abuse
  • GC/MS
  • Immunoassay of drugs in urine
  • Opiates
  • Prenatal and neonatal drug exposures

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Clinical Biochemistry

Cite this

Modification of screening immunoassays to detect sub-threshold concentrations of cocaine, cannabinoids, and opiates in urine : Use for detecting maternal and neonatal drug exposures. / Hattab, Eyas M.; Goldberger, Bruce A.; Johannsen, Laura M.; Kindland, Pat W.; Ticino, Frances; Chronister, Chris W.; Bertholf, Roger L.

In: Annals of Clinical and Laboratory Science, Vol. 30, No. 1, 01.2000, p. 85-91.

Research output: Contribution to journalArticle

Hattab, Eyas M. ; Goldberger, Bruce A. ; Johannsen, Laura M. ; Kindland, Pat W. ; Ticino, Frances ; Chronister, Chris W. ; Bertholf, Roger L. / Modification of screening immunoassays to detect sub-threshold concentrations of cocaine, cannabinoids, and opiates in urine : Use for detecting maternal and neonatal drug exposures. In: Annals of Clinical and Laboratory Science. 2000 ; Vol. 30, No. 1. pp. 85-91.
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