Digestive Diseases and Sciences, VoL 41, No. 9 (September 1996), pp. 1749-1753 Utility of Clinical Symptoms versus Laboratory Tests for Evaluation of Acute Gastroenteritis YEHUDA CARMELI, MD, MATI'HEW SAMORE, MD, ORLY SHOSHANY, MD, ANDREA RAJS, PhD, and RUTH STALNIKOWITZ, MD Our purpose was to find the utility of laboratory tests in emergency ward evaluation of patients with gastroenteritis. Medical records of 163 adult cases were retrospectively re- viewed. Blood laboratory tests were drawn in 116 cases, 78 had at least one abnormality. Urine tested ketone-positive in 15 of 116 cases. One hundred fifteen were treated with intravenous fluids, 20 with antibiotics, and 4 were admitted. Fifty-eight stool cultures were sent, and 13 yielded enteric pathogens. Cultures from patients with fever or symptoms of long duration had higher yields (57% vs 11.3% and 38.1% vs 0%, P < 0.001, respectively), and when combined had sensitivity of 100% and specificity of 65%. There was no association between abnormal blood laboratory results, intravenous hydration, and antibiotic treatment with the stool culture being positive or with the patient being hospitalized. Laboratory tests are used often, but are very seldom contributory for evaluating domestically acquired gastroenteritis. KEY WORDS: gastroenteritis; infectious diarrhea; utility; clinical symptoms; laboratory evaluation; adults. Gastroenteritis accounts for 5% of visits to emer- gency wards and is second only to the common cold as a cause of days lost from work (1). Therefore, it is an extreme economic and public health burden. Infec- tious gastroenteritis is caused by multiple agents: viruses, bacteria, and parasites. The distribution of the causative organisms varies among different geo- graphical areas, and in developed countries most of the cases are nonbacterial (2, 3). Infectious gastroen- teritides can be divided into three categories: travel- er's diarrhea, antibiotic-associated diarrhea, and do- mestically acquired diarrhea. Domestically acquired gastroenteritis in adults is most often a self-limited Manuscript received February 19, 1996; accepted June 14, 1996. From the Department of Medicine and Infectious Diseases, Hadassah University Hospital, Mount Scopus, Jerusalem, Israel; and the Division of Infectious Diseases New England Deaconess Hospital, Boston, Massachusetts. Address for reprint requests: Dr. Yehuda Carmeli, Division of Infectious Diseases, New England Deaconess Hospital, 1 Deacon- ess Road, Boston, Massachusetts 02215. Digestive Diseases and Sciences, Vol. 4L No. q (September 1996) condition, of few days' duration, and for which hos- pitalization is needed infrequently. In evaluating a patient with gastroenteritis, the physician has to make clinical decisions: should the patient be hydrated? Should stool culture be sent? Should antibiotics be prescribed? Should the patient be admitted? In the process of evaluation and treat- ment of patients with gastroenteritis laboratory tests are often used to help make these decisions. Blood electrolytes, complete blood count, fecal blood and leukocytes, and urine ketones are frequently used. These tests add to the cost of treatment and their value in assisting clinical decision making is not clear. We conducted this study in order to find how often different laboratory tests are used in the evaluation of patients presenting to the emergency ward with do- mestically acquired gastroenteritis and to determine the utility of laboratory tests in assisting the physician in clinical decision making. 1749 0! 63-2116/96/0900-1749509.50/0 © 1996Pit:humPublishing Corporation