The Accuracy of Drug Use Monitoring in Methadone Treatment

Abstract

Patients' urinalysis results are used in methadone maintenance programs to help make decisions about methadone dosage, medication take-home privileges, referrals for employment and job training and detoxification from methadone. Little systematic research exists, however, addressing the adequacy of the procedures used to detect illicit drug use. This study examined the accuracy of patients' clinic thin-layer chromatography (TLC) urinalysis profiles by comparing these with two independent measures of drug use; patient self-reports of drug use and urinalysis using a more sensitive test, enzyme immunoassay (EMIT). A representative sample of 229 patients in three methadone clinics was studied. The study found that drug use as measured by self-reports or by EMIT is 2.5 times higher than use as measured by TLC. The level of agreement between self-reports and EMIT was high, while the levels of agreement between these measures and clinic TLC urinalysis were low. Clinic decisions about take-home medication were shown to be correlated with clinic urinalysis results. The study examines the causes and consequences of inaccurate drug screening and discusses possible alternative responses to the problem for the methadone treatment field.