Introduction. A drug screen is a frequent investigation in the emergency department. The purpose of ordering this test is to determine whether the patient's condition is due to a drug. The purpose of this review is to address the question -do you really need that emergency drug screen? Background. A screening test is an investigation performed upon a defined population to identify subclinical disease. A diagnostic test confirms a specific disease in a particular patient who is at risk of that

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... ndition because of the medical history or physical examination. Diagnostic tests have optimal performance characteristics that differ from those of screening tests. Therefore, an optimal screening test cannot be an optimal diagnostic test. Literature review. The relevant literature was identified through electronic search augmented by subsequent search of reference lists of the primarily identified publications. Articles not dealing with emergency qualitative urine drug screening of emergency department patients were not considered. Results. There were seven retrospective case series describing 1,405 patients, one prospective case series of 196 patients, and one randomized trial of 117 patients. There were three retrospective case series describing 694 children. For patients presenting with psychiatric symptoms, there were two retrospective case series totaling 557 patients and one randomized trial of 392. There were three retrospective case series in 3,509 multiple trauma patients. There was no significant impact upon the management of these patients in the emergency department. Conclusion. The emergency drug screen is unlikely to impact significantly upon the management of the patient in the emergency department.