Urine drug screens (UDSs) are often performed in the emergency department (ED) as part of a standard ED order set in patients with significant altered mental status, trauma, or seizures usually without the patient’s knowledge or specified informed consent. In the ED the UDS has been included in the standard consent to treatment for routine testing along with blood studies, EKG, urinalysis and radiology. Many technical factors are known to effect UDS results.There is a lack of education among physicians regarding the clinical pitfalls of UDS interpretation. This article discusses the current state and issues associated with the UDS, and presents three clinical vignettes that illustrate the impact of false-positive UDS results on patient care and the potential for a patient becoming unknowingly and unfairly stigmatized. The article also offers suggestions including a requirement for either formal informed consent or an “opt out” screening process, as recommended by the CDC in HIV testing, designed to protect patient autonomy and confidentiality.