Vanilmandelic Acid (VMA), 24 Hrs Urine

Vanillylmandelic acid (VMA) is an end product of the catecholamines, epinephrine, and norepinephrine metabolism. The vanillylmandelic acid (VMA) test is used to diagnose or rule out conditions like neuroblastoma, pheochromocytoma and other neuroendocrine tumors and to monitor the effectiveness of treatment. Vanillylmandelic acid (VMA) test is done when symptoms such as abdominal mass, bruising around the eyes, trouble in walking, or bone pains are seen in a child and when there are symptoms of increased catecholamine levels such as persistent or episodic hypertension, severe headaches, increased heart rate, and sweating. Vanillylmandelic acid (VMA) test may be done along with an homovanillic acid (HVA), urine creatinine to diagnose a neuroblastoma, to monitor the effectiveness of treatment, and to monitor recurrence. A urine creatinine useful to report a VMA-to-creatinine and HVA-to-creatinine ratios which compares the rate of VMA and HVA excretion. Plasma free metanephrines, urine metanephrines, and urine or plasma catecholamine tests have now replaced a VMA test to detect pheochromocytomas. Howevever, the VMA test may still be done along with one or more of the above tests for the detection of a pheochromocytoma.

1. Why is a 24 hour urine sample required?

The amount of VMA excreted in the urine fluctuates during the course of a day. By collecting all the urine for 24 hours, the average amount of VMA can be measured which is a better indicator of whether levels are increased or not.

2. Will medication affect the levels of VMA?

Certain drugs can increase or decrease the levels of VMA. However, prior intimation before sample collection and interpretation of test results is useful.

3. Why are some people at a higher risk for developing a pheochromocytoma or neuroblastoma?

People with a family history of multiple endocrine neoplasia (MEN2), a genetic condition are at higher risk for developing a pheochromocytoma and developing it at a younger age.