#ExistRefRange>Normetanephrine: 0.0-0.89 nmol/L
Metanephrine: 0.0-0.49 nmol/L
#ExistInterpData>: This test is useful in the detection of pheochromocytoma, a rare neuroendocrine tumor. The majority of patients with pheochromocytoma have a plasma normetanephrine concentration in excess of 2.2 nmol/L and/or a metanephrine concentration in excess of 1.1 nmol/L. Increased concentrations of these analytes serve as confirmation for diagnosis. Patients with essential hypertension and plasma concentrations of normetanephrine below 0.9 nmol/L and/or a metanephrine concentration below 0.5 nmol/L, can be excluded from further testing. If clinical suspicion remains, repeat testing or testing for metanephrines in a 24-hr. urine specimen should be considered.
||Isoetharine, isoproterenol, 3,4-methylenedioxyamphetamine (MDA), and 3,4-methylenedioxymethamphetamine (MDMA) are known to interfere in this test.
Many drugs/medications, including over-the-counter and herbal products, can interfere with test results. Testing for all potential interactions is not possible. If the patient is taking a drug not listed as an interferent, its potential effect on test results is unknown. If test results are inconsistent with clinical evidence, drug interference should be considered. If appropriate, the patient should discontinue the potential interferent for 48-72 hours and a new sample collected for retesting.
||Metanephrine (Metanephrines, Plasma (Free)), Metanephrines, Fractionated (Metanephrines, Plasma (Free)), Normetanephrine (Metanephrines, Plasma (Free)), Quantitative Metanephrines (Metanephrines, Plasma (Free))