title: Monitoring cocaine use in substance-abuse-treatment patients by sweat and urine testing.
abstract: Sweat and urine specimens were collected from 44 methadone-maintenance patients to evaluate the use of sweat testing to monitor cocaine use. Paired sweat patches that were applied and removed weekly (on Tuesdays) were compared with 3-5 consecutive urine specimens collected Mondays, Wednesdays, and Fridays. All patches (N = 930) were extracted in 2.5 mL of solvent and analyzed by ELISA immunoassay (cutoff concentration 10 ng/mL); a subset of patches (N = 591) was also analyzed by gas chromatography-mass spectrometry (GC-MS) for cocaine, benzoylecgonine (BZE), and ecgonine methyl ester (EME) (cutoff concentration 5 ng/mL). Urine specimens were subjected to qualitative analysis by EMIT (cutoff 300 ng/mL) and subsets were analyzed by TDx (semiquantitative, LOD 30 ng/mL) and by GC-MS for cocaine (LOD 5 ng/mL). Results were evaluated to (1) determine the relative amounts of cocaine and its metabolites in sweat; (2) assess replicability in duplicate patches; (3) compare ELISA and GC-MS results for cocaine in sweat; and (4) compare the detection of cocaine use by sweat and urine testing. Cocaine was detected by GC-MS in 99% of ELISA-positive sweat patches; median concentrations of cocaine, BZE, and EME were 378, 78.7, and 74 ng/mL, respectively. Agreement in duplicate patches was approximately 90% by ELISA analysis. The sensitivity, specificity, and efficiency of sweat ELISA cocaine results as compared with sweat GC-MS results were 93.6%, 91.3%, and 93.2%, respectively. The sensitivity, specificity, and efficiency between ELISA sweat patch and EMIT urine results were 97.6%, 60.5%, and 77.7%, respectively. These results support the use of sweat patches for monitoring cocaine use, though further evaluation is needed.
authors.affiliation: National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Preston
authors.forename: M A
authors.initials: MA
authors.lastname: Huestis
authors.forename: C J
authors.initials: CJ
authors.lastname: Wong
authors.forename: A
authors.initials: A
authors.lastname: Umbricht
authors.forename: B A
authors.initials: BA
authors.lastname: Goldberger
authors.forename: E J
authors.initials: EJ
authors.lastname: Cone
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003042:Cocaine / Q000031:analogs & derivatives / Q000032:analysis / Q000652:urine*; D019970:Cocaine-Related Disorders / Q000188:drug therapy / Q000652:urine*; D017248:Enzyme Multiplied Immunoassay Technique; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods*; D013542:Sweat / Q000737:chemistry*
chemical_list: C005618:benzoylecgonine; D003042:Cocaine; D008691:Methadone; C034524:ecgonine methyl ester