Frequency of abnormal results in screening laboratory tests and associated interventions in emergency psychiatric services.

Aim: Screening laboratory tests for patients with acute psychiatric symptoms are discouraged in general emergency services but are recommended by emergency psychiatric guidelines due to the high prevalence of abnormal findings in severe psychiatric patients. The present study aimed to evaluate the utility of screening laboratory tests in a real-world, emergency psychiatric setting through focusing on how often abnormal values lead to medical interventions. Methods: The electronic medical records were reviewed for adult patients who were involuntarily admitted to Tokyo Metropolitan Matsuzawa Hospital for an imminent risk of self-harm or harm to others between October 2019 and September 2022. The number of patients, abnormal screening laboratory findings, and medical interventions were examined. Results: Of the 600 patients identified in the review, 595 had abnormal laboratory findings, but only 97 (16.3%) underwent medical interventions related to these results. Frequently observed abnormal findings, such as elevated creatine kinase and an elevated white blood cell count, were often attributed to the patient's agitation or were considered clinically nonsignificant. Notably, one-third of the interventions prompted by laboratory findings resulted only in additional testing. More than half of the treatments were either of questionable necessity or nonurgent. Medical interventions other than additional tests were more likely to be prompted by the patient's medical history and presentation. Conclusion: In the emergency psychiatric setting, abnormal laboratory findings are common, but clinical decisions largely rely on the patient's medical history and presentation, with few requiring immediate interventions. A history-driven approach may enhance the clinical value of laboratory tests.