Study Objective: To determine the utility of routine laboratory screening of patients who are evaluated and admitted for severe depression, active suicidal thoughts, or other mood disorders without psychotic or manic features. Patients in this diagnostic spectrum comprise over half of all patients admitted to our mental health service.
Methods: Study Design: This is a retrospective case series of 150 consecutive patients.
Study Setting: All patients included in this study were evaluated at a single urban tertiary care hospital with an annual emergency department census of 65,000 patients.
Study Participants: The primary inclusion criteria were a) any psychiatric evaluation in the emergency department (ED), regardless of presenting chief complaint, and b) hospital admission, regardless of final diagnosis or disposition. Exclusion criteria were: age 18 years, known overdose or suspicion of overdose, psychosis, mania, agitation, dementia or a history/physical examination that independently warranted laboratory evaluation.
Data Analysis: A consecutive list of 750 patients with any psychiatric evaluation in the emergency department was obtained. For any patient who was ultimately admitted to the hospital, the history of present illness, review of systems and physical exam were reviewed to determine study eligibility. ED notes, laboratory studies, follow-up studies, medication administration logs, prescription histories and discharge summaries were reviewed. Abnormal laboratory values and pertinent management events were tabulated.
Results: Routine laboratory studies resulted in minimal changes in clinical management in our study sample. As a consequence of routine laboratory screening, 2 patients received single doses of oral potassium supplementation, 1 patient was treated for an asymptomatic urinary tract infection, and eleven patients who denied drug use were discharged with instructions to abstain from substance abuse. Laboratory screening resulted in no cases of sustained changes in medical management and no changes of inpatient or discharge disposition. Six patients were discharged with new diagnoses as a direct result of laboratory screening: 5 with mild anemia and 1 with urinary tract infection. All of these patients were asymptomatic.
Conclusion: In the easily identifiable and prevalent subset of psychiatric patients included in this study (medically asymptomatic patients with isolated depression, suicidal intent, or other mood disturbances without psychotic features or mania), routine ED laboratory screening of is minimally useful. Prior studies of routine laboratory evaluation in psychiatric patients have come to disparate conclusions. All prior studies have included at least some patients with mania, agitation, psychosis or dementia, all of which are features that are more likely to be mistaken with delirium than isolated mood disorders.