Vanillylmandelic Acid (VMA), Urine

Major metabolite of catecholamine, historically has been used to screen pheochromocytoma. The current recommended test now is fractionated plasma free metanephrines.

Other names: 3-methoxy-4-hydroxymandelic acid and 4-hydroxy-3- methoxymandelic acid.

Normal range: 0 " “7 mg/day.

Use

Screening for catecholamine-secreting tumors in children when accompanied by HVA

Supporting a diagnosis of neuroblastoma

Monitoring neuroblastoma treatment

Interpretation

Increased In

Pheochromocytoma

Paraganglioma

Neuroblastoma

Limitations

Patients should avoid salicylates, caffeine, phenothiazine, and antihypertension agents, as well as coffee, tea, chocolate, and fruit (especially bananas and any vanilla-containing substances for 72 hours prior to collection).

Some neuroblastoma patients are positive for urinary homovanillic acid abnormality but do not excrete increased VMA. Twenty to thirty-two percent of patients with neuroblastoma do not have elevation of VMA. Many have other laboratory abnormalities such as increased metanephrines, HVA, or dopamine.