Urine drug tests (UDTs) have a limited but important role in managing patients with substance use disorders and should be guided by a care plan that will be meaningfully changed by the results. The unregulated drug market is encumbered by an evolving milieu of drug additives and contaminates which can complicate the interpretation of simplistic urine drug testing. In particular, testing by immunoassay without confirmation by mass spectrometry can fail to detect potent drugs that can be harmful. Immunoassays are also well known for false positives that can mislead patient management. Mass spectrometry testing delivers the most reliable and comprehensive results, but with delayed turnaround time. Clinicians that are considering drug testing should consider consulting with the laboratory for advice on choosing the best test methodology available and for help interpreting the results.
Sources:
American Society of Addiction Medicine, Appropriate Use of Drug Testing in Clinical Addiction Medicine Consensus Document.
Centre for Addition and Mental Health (CAMH), Canadian Opioid Use Disorder Guideline.
CLSI. Toxicology and Drug Testing in the Medical Laboratory. 3rd ed. CLSI guideline C52. Kyle, P.B., Fuller, D.C., Garg, U., Hammett-Stabler, C.A., Hoess, E., Johnson-Davis, K., Kapur, B.M., Langman, L.J., LeGatt, D.F., Loughmiller, D., Pesce, A., Sadek, W., Smith, M.P., Watson, I.D., Wolf, C.E., Wu, A., Zhang, Y.V. Clinical and Laboratory Standards Institute; 2017.
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