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Vanillylmindic acid in the urine
Last reviewed: 05.07.2025
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Reference values (norm) for urinary excretion of vanillylmandelic acid are up to 35 μmol/day (up to 7 mg/day).
The function of the adrenal medulla can be assessed by examining the content of vanillylmandelic acid in urine, the end product of tissue metabolism of dopamine.
Normally, of the total amount of catecholamines secreted by the adrenal glands during the day, only approximately 1% is excreted in the urine unchanged (adrenaline 0.36-1.65%, noradrenaline 1.5-3.3%), while in the form of vanillylmandelic acid - up to 75%. From a clinical point of view, the determination of vanillylmandelic acid in the urine is especially helpful in the diagnosis of pheochromocytoma and neuroblastoma.
It should be remembered that up to 50% of studies can give false negative results, so it is recommended to determine vanillylmandelic acid in freshly collected urine immediately after a hypertensive crisis.
The sensitivity of this test for the diagnosis of pheochromocytoma is 28-56%, specificity is 98%.
Approximately 15-20% of patients with neuroblastoma have normal urinary vanillylmandelic acid levels, but elevated metanephrine and normetanephrine levels, so all of these metabolites need to be tested.