Measurement of Urinary Metanephrines to Screen for Pheochromocytoma in an Unselected Hospital Referral Population

diagnosis is important because of the dangers of uncon-trolled severe hypertension and the availability of very effective surgical treatment. Urinary or plasma cat-echolamines or catecholamine derivatives are com-monly used to screen for pheochromocytomas before imaging, but data from 24-h urinary metanephrine re-sults, patient age, and sex may better predict tumors in populations with a low pretest probability. Methods: We retrospectively studied outcomes of an unselected population (1819 patients) referred to a ter-tiary hospital laboratory for urinary metanephrine test-ing and investigated the usefulness of some simple derivative measures for detecting pheochromocytoma. We normalized values for urinary 24-h excretion of metanephrine, normetanephrine, and 3-methoxytyra