Urine drug testing is an important component of opioid prescribing.
About Urine Drug Tests:
- Initial tests are generally done with immunoassays.
- Risk include:
- False negatives due to cut-offs for test sensitivity
- False positive due to cross reactivity with other drugs.
- Follow-up unexpected findings: Send for further analysis using gas chromatography/mass spectroscopy to identify specific compounds.
- Be aware of opioid metabolic pathways to fully analyze test results (see figure below).
Important: Urine drug testing: Must be integrated and synthesized the patient’s entire history and clinical picture.
- Etiology of a particular test result cannot determined. (i.e. If the urine test is negative for opioids, unknown if patient diverting medication vs. using more rapidly than directed).
- Dedicated deceivers can beat the system.
See also:
Sources:
- Christo PJ et al. Urine drug testing in chronic pain. Pain Physician 2011;14:123-143.
- Heit HA and Gourlay DL. Urine drug testing in pain medicine. J Pain Symptom Manage 2004;27:260-267.
- Peppin JF et al. Recommendations for urine drug monitoring as a component of opioid therapy in the treatment of chronic pain. Pain Medicine 2012;13:886-896.
- Reisfield GM et al. ‘False-positive’ and ‘false-negative’ test results in clinical urine drug testing. Bioanalysis 2009;1(5):937-952.