Use of Urine Electrolytes and Urine Osmolalityin Clinical Diagnosis of Fluid, Electrolytes, and Acid-Base Disorders

Abstract We discuss the use urine electrolytes and osmolality in the clinical diagnosis in patients with fluid, electrolytes and acid-base disorders, emphasizing their physiological basis, their utility and the caveats and limitations in their use. While our focus is on information obtained from measurements in the urine, clinical diagnosis in these patients must integrate information obtained from the history, the physical examination and other laboratory data.