Advances in metanephrine testing for the diagnosis of pheochromocytoma.

Pheochromocytoma is a lethal tumor of chromaffin cells of the adrenal medulla that produces episodes of hypertension with the symptoms of palpitations, severe headaches, and sweating. The diagnosis of pheochromocytoma is a challenging one; autopsy series suggest that many pheochromocytomas are not clinically suspected, and the undiagnosed tumor can be associated with morbid consequences. The testing of catecholamines, metanephrines, and Vanillylymandelic acid commonly is used for screening of pheochromocytoma. The diagnostic value of various biochemical tests,as reported in recent Mayo and National Institutes of Health studies, have been compared and discussed in detail. The recent developments in the methodologies of metanephrines testing also are presented.