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.