Pheochromocytoma are uncommon tumors that are exceedingly dangerous and often difficult to diagnose. To improve diagnostic accuracy, we recently developed a new technique for measuring plasma concentrations of free metanephrines, using HPLC and electrochemical detection. We continue to use this test, along with other standard tests, to screen patients for pheochromocytoma. We are evaluating patients with hereditary pheochromocytoma, especially von Hippel-Lindau disease (VHL), on a regular schedule to determine when plasma metanephrines become positive in comparison to the other tests for this tumor. Preliminary results indicate that plasma metanephrines are often the first test to become positive in the diagnosis of pheochromocytoma. VHL kindreds, particularly those with a history of pheochromocytoma, must be carefully and repeatedly screened to prevent the potential morbidity and mortality from an undiagnosed pheochromocytoma and plasma metanephrines are proving to be very useful, in this regard.
