Urine Drug Screen

Last edited on April 7, 2022

The Urine Drug Screen (UDS) has several limitations, including only testing for a limited for a number of drugs, plus false positives/negatives are common. There can be a lack of temporal correlation with the UDS result and the clinical presentation. Urine drug screens at one hospital are also not always the same at another site.

Should Urine Drug screens Ordered Routinely in the ER?

Urine drug screens at the emergency department level does not improve the routine management of psychiatric patients.^[1]^[2] However, despite its limitations, the urine drug screen is useful for psychiatrists when there are challenges in determining a whether a patient has a primary psychotic disorder versus a substance-induced psychotic disorder.^[3]

See also: Dakota, S. (2016). Urine Drug Screening: Minimizing False-Positives and False-Negatives to Optimize Patient Care. US Pharm, 41(8), 26-30.

See also: Moeller, K. E., et al. (2017, May). Clinical interpretation of urine drug tests: what clinicians need to know about urine drug screens. In Mayo Clinic Proceedings (Vol. 92, No. 5, pp. 774-796). Elsevier.

See main article: Opioid Use Disorder (OUD)

Carbamazepine, cyclobenzaprine, and quetiapine can all trigger a false positive for TCAs.^[4]
There have been case reports of lamotrigine causing false positive phencyclidine readings on urine drug screen.^[5]

effects-and-monitoring

¹⁾ Tenenbein, M. (2009). Do you really need that emergency drug screen?. Clinical Toxicology, 47(4), 286-291.

²⁾ Kroll, D. S., Smallwood, J., & Chang, G. (2013). Drug screens for psychiatric patients in the emergency department: evaluation and recommendations. Psychosomatics, 54(1), 60-66.

³⁾ Latt, N., Jurd, S., Tennant, C., Lewis, J., Macken, L., Joseph, A., ... & Long, L. (2011). Alcohol and substance use by patients with psychosis presenting to an emergency department: changing patterns. Australasian psychiatry, 19(4), 354-359.

⁴⁾ Saitman, A., Park, H. D., & Fitzgerald, R. L. (2014). False-positive interferences of common urine drug screen immunoassays: a review. Journal of analytical toxicology, 38(7), 387-396.

⁵⁾ Geraci, M. J., Peele, J., McCoy, S. L., & Elias, B. (2010). Phencyclidine false positive induced by lamotrigine (Lamictal®) on a rapid urine toxicology screen. International journal of emergency medicine, 3(4), 327-331.