Vanillylmandelic acid, urine
Vanillylmandelic acid (VMA) is one of the metabolites of the catecholamines epinephrine (adrenaline) and norepinephrine. This test measures the amount of VMA that is excreted into the urine, typically over a 24-hour period, to detect excess catecholamine production.
VMA is usually present in the urine in small fluctuating amounts that only increase appreciably during and shortly after the body is exposed to a stressor. Neuroblastomas, pheochromocytomas, and other neuroendocrine tumors, however, can produce large amounts of catecholamines, resulting in greatly increased concentrations of the hormones and their metabolites. The hormone releases can cause persistent hypertension, severe headaches, palpitations, sweating, nausea, anxiety, and tingling in the extremities.
For a 24-hour urine collection, all of the urine produced during a 24-hour period should be saved. It is important that the sample be refrigerated during this time period. A single urine sample is collected for a random urine test.
- Sample of urine
- We perform the test in 24 hours from sampling