VMA (Vanillyl Mandelic Acid) - Quantitative, Urine 24 Hrs

Catecholamines include dopamine (found mostly in the central nervous system), norepinephrine (mainly in the sympathetic nervous system) and epinephrine (mainly in the adrenal medulla). They are stored as an inactive complex. Released catecholamines, having a short half-life, are taken up by sympathetic nerve endings, or metabolized by the liver and kidney and excreted. Vanillylmandelic acid (VMA) and 4-hydroxy-3-methoxy-mandelic acid (HMMA) are the end product of both epinephrine and norepinephrine catabolism. Quantitation of acidic metabolites has long proven to be a reliable diagnostic as well as a commonly used follow-up procedure for pheochromocytoma and other catecholamine-producing tumors. The prevalence of pheochromocytoma is 0.1% to 0.2% in hypertensive patients. Pheochromocytomas have a long record of misdiagnosis due to the metabolic, cardiac and gastrointestinal symptoms that can mimic many other diseases. These if undetected or mistreated can be fatal. However, since this is a surgically curable disease early diagnosis by demonstration of excess VMA excretion is critically important.