To evaluate the utility of sweat testing for monitoring opiate use, sweat patch drug analysis was compared to urine screens in 44 methadone maintenance patients. Drug test results from 1065 urine specimens collected Mon-Wed-Fri (EMIT-cutoff 300 ng/mL) and 710 sweat patches applied each Tue and worn for 7 days were compared. All sweat patches were analyzed for opiates by ELISA immunoassay (cutoff 10 ng/mL); a subset of sweat patches (N=389) were analyzed by GC/MS (cutoff 5 ng/mL) for heroin, morphine, 6-acetylmorphine and codeine. To determine the window of detection of opiate use in sweat patches, results of urine specimens collected over 4 different intervals were compared with each Tue sweat patch result. Agreement between the paired sweat and urine results were as follows: 1) 78.6% for 3 specimens collected the following Wed., Fri, Mon; 2) 76.6% for 4 specimens collected the preceding Mon, and the following Wed, Fri, Mon; 3) 76.9% for 4 specimens collected the following Wed, Fri, Mon, Wed; and 4) 75.8% for 5 specimens collected the preceding Mon and the following Wed, Fri, Mon, Wed. Accuracy, sensitivity and specificity of sweat ELISA compared to sweat GC/MS were 89.5%, 96.7%, and 72.2%. Median GC/MS concentrations of heroin, 6-acetylmorphine, morphine and codeine were 10.5, 13.6, 15.9, and 13.0 ng/mL, respectively. ELISA sweat tests detected less opiate use than urine testing; however, sweat patches provide the advantage of monitoring drug use for periods of up to one week or longer.
ASJC Scopus subject areas
- Pharmacology (medical)