Utility of Urine Drug Testing in Outpatient Addiction Evaluations

Data examining usefulness of urine drug testing in addiction settings for accurately establishing diagnoses and informing treatment is limited. In this retrospective-cohort study we examined the utility of performing urine drug testing in patients presenting for an outpatient addiction assessment.

Urine drug testing and patient-reported substance use history were obtained from the medical record of patients who presented for an outpatient addiction evaluation. Patients who denied use of a substance within the window of detection but tested positive were considered to have misrepresented their use. Differences between patients accurately representing versus misrepresenting their use were evaluated. Sensitivity/specificity of drug tests were calculated from self-report and changes to treatment recommendations and diagnoses assessed.

One hundred and seventy-four patients (mean age = 43.35 ± 15.68 years) were included and the sample was majority male (67%). Ninety-four (54%) patients reported use of a substance within the window of detection. Of 80 patients denying recent use, 14 tested positive (8%). There were no differences in sex (P = 0.78) or age (P = 0.12); referral sources differed significantly between correct and incorrect responders (P = 0.01). Specificity varied between 96% and 99%, while sensitivity had a wider range (17%-87%). Treatment recommendations and diagnoses were altered after review of drug testing results in 1 patient (0.5%). However, in the remainder, all patients were already diagnosed with a severe substance use disorder and had received recommendations to initiate residential/outpatient substance use treatment.

Among patients completing urine drug testing during outpatient substance use disorder evaluation positive screens alerted providers to undisclosed persistent substance use and potential withdrawal in 8% of the cohort and resulted in a change in diagnoses and/or treatment in 1 patient.