Effects of mandatory screening labs in directing the disposition of the apparently healthy psychiatric patient in the emergency department.

Objective: To determine whether mandatory psychiatric admission laboratory tests yield results that change the disposition of a patient with primary psychiatric complaint from admission to a psychiatric service to admission to a medical service.

Methods: This was a single center retrospective cohort chart review study approved by the facility Institutional Review Board in which we used a records database maintained by the emergency department's social workers to access the records of every patient that presented to our emergency department with a psychiatric chief complaint between the dates of December 1, 2011, and December 1, 2013. We focused on those that were admitted to either a psychiatric service or a medical service after a thorough evaluation by the department of social work and an emergency provider. We applied our inclusion and exclusion criteria and reviewed the results of the mandatory psychiatric laboratory tests (complete blood count, comprehensive metabolic panel, thyroid stimulating hormone, acetaminophen, aspirin, blood alcohol level, urinalysis, urine pregnancy test, urine drug screen) required for admission. Our independent variables were the compulsory psychiatric admission laboratory tests and our dependent variable was the admission to a medical service.

Results: Of 5,606 laboratory tests that were ordered and produced results for the 682 patients enrolled in our study, 51 results were considered clinically significant abnormal results, or results requiring treatment prior to psychiatric service admission, by the 2 reviewing emergency physicians. Only one of 682 psychiatric patients received a final disposition to a medical service based upon abnormal laboratory studies. That patient presented without any medical complaints but a chief complaint of "suicidal ideation," and was found to have diabetic ketoacidosis. Based on our data, the probability that an abnormal laboratory test will result in a change in disposition is 1/682=0.1% (95% CI: 0.0% to 0.9%).

Conclusion: Patients presenting to the emergency department with a psychiatric chief complaint and no physical complaints, abnormal vital signs, or abnormal physical exam findings have less than 1% probability that an abnormal laboratory study will change their disposition from a psychiatric admission to a medical admission.