Evaluate the presence of abnormal catecholamine production, diagnose pheochromocytoma, neuroblastoma and ganglioneuroblastoma. Slightly elevated concentrations of urinary metanephrines (900-1300 ug/24 hr) are usually associated with essential hypertension, intense physical activity, emotional and physical stress, drug interferences and improper specimen collection. Higher concentrations (greater than 1300 ug/24 hr) are suggestive of pheochromocytoma.