Metanephrines, Total, Urine Unit Converter

Total urine metanephrines measures the combined amount of metanephrine and normetanephrine excreted in a 24-hour urine collection. These are the O-methylated breakdown products of the catecholamines epinephrine (adrenaline) and norepinephrine (noradrenaline).

Catecholamines are produced by the adrenal glands and sympathetic nervous system. After they perform their actions, they are broken down into metanephrines and then further metabolized. Both the hormones and their metabolites are eliminated in urine.

This test is used primarily to detect catecholamine-producing tumors such as pheochromocytoma and paraganglioma, collectively known as PPGL. These rare tumors can cause dangerously high blood pressure and other serious cardiovascular complications if left untreated.

Metanephrines are produced primarily in the adrenal medulla, where catechol-O-methyltransferase (COMT) converts epinephrine to metanephrine and norepinephrine to normetanephrine. They are also produced in smaller amounts by sympathetic nerve cells throughout the body.