Urine Drug Screen

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]
  • 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]