Vanilmandelate Test

Your body runs on two stress hormones, adrenaline and noradrenaline, that govern your heart rate, blood pressure, and alertness. When those hormones do their job, your body breaks them down into a single end-product that gets sent out in your urine. Measuring that end-product gives you a window into how active your stress hormone system has been over hours and days, not just at the moment of a blood draw.

VMA (vanillylmandelic acid) is the name of that end-product. The test is most famous as a tool for catching rare adrenal tumors that quietly pump out stress hormones, but it also reflects how hard your sympathetic nervous system, the wiring that drives your fight-or-flight response, has been working. For someone tracking their physiology over time, a high or low result can signal something worth investigating long before symptoms become obvious.

What This Marker Reflects

Adrenaline is made by your adrenal glands, the two small organs that sit on top of your kidneys. Noradrenaline is released by the nerve endings that run throughout your body and connect to your heart, blood vessels, and other organs. After these hormones do their job, your body breaks them down through a series of steps, mostly inside nerve cells and the liver, until what is left is VMA. That final molecule cannot be recycled. It exits in your urine.

Because VMA is the final stop on this metabolic road, its level in urine reflects how much adrenaline and noradrenaline your body has produced and broken down over many hours. That is why a urine collection captures something closer to a moving average than a snapshot in time.

Rare Adrenal and Nerve Tumors

The classic reason to measure VMA is to look for pheochromocytoma, a rare tumor of the adrenal gland that secretes adrenaline and noradrenaline in unpredictable bursts. It can cause episodes of pounding heart rate, sweating, headaches, and dangerously high blood pressure that a standard checkup may miss between attacks. In a study of 159 adults, 24-hour urinary VMA caught about 72 out of every 100 cases (72% sensitivity), with very few false alarms (96% specificity). Urinary free metanephrines, a related test, caught 100 out of 100 in the same study, which is why metanephrines are now the front-line screening test.

In a separate cohort of 491 people with adrenal tumors, a 24-hour urinary VMA threshold corresponded to about 85 out of 100 pheochromocytomas being detected (85% sensitivity, 91% specificity). VMA also has a practical advantage over its competitors: it is less likely to be thrown off by common drugs like acetaminophen, so it can rescue a workup when the metanephrine result is uninterpretable. Treatment for these tumors is surgical removal, and falling VMA after surgery is one of the signs the operation worked.

In children, elevated VMA is one of the standard markers for neuroblastoma, a tumor of the sympathetic nervous system. About 75 to 85 out of 100 children with neuroblastoma show elevated urinary VMA at diagnosis. This is a pediatric disease and not typically what brings adults to this test, but it explains why VMA has been studied so deeply.

Sympathetic Stress and Cardiovascular Events

VMA also rises with acute stress on the cardiovascular system. In a study of 22 people after a heart attack, urinary VMA, adrenaline, and noradrenaline were all significantly elevated in the first days afterward. Higher excretion was linked to low blood pressure, heart failure, and serious heart rhythm disturbances during the recovery period, reflecting how intensely the sympathetic nervous system had been activated.

More subtly, ongoing sympathetic activation from environmental exposures can show up in VMA. In a cross-sectional study of 696 adults, exposure to volatile organic compounds was associated with elevated markers of sympathetic activation. These findings position VMA as a long-window read on stress hormone output, useful for context when other markers of cardiovascular strain are also abnormal.

Environmental and Occupational Exposures

Chronic exposure to certain metals and chemicals shifts VMA by interfering with the catecholamine pathway itself, not just by stimulating it briefly:

• Manganese: in 58 smelter workers, higher manganese in blood and urine tracked with higher urinary VMA and HVA (homovanillic acid, a related breakdown product), consistent with disrupted catecholamine metabolism.
• Lead: in 131 lead-exposed workers, urinary HVA was elevated and VMA modestly increased compared to controls.
• Carbon disulfide: in 108 rayon factory workers, higher cumulative exposure correlated with lower urinary VMA and HVA, suggesting long-term suppression of the catecholamine system.

Reduced Sympathetic Output

A low VMA is not always a clean signal, but it can mean your sympathetic nervous system is running cooler than expected. In a study of 109 children with craniopharyngioma, a tumor near the base of the brain that can damage the hypothalamus, those with hypothalamic involvement had significantly lower urinary VMA and HVA than those without. The low values tracked with reduced physical activity and severe obesity, interpreted as a drop in sympathetic drive. In the volunteer workers exposed long-term to carbon disulfide, low VMA reflected toxic suppression of catecholamine turnover.

Reconciling High and Low

VMA is not a simple "higher is bad" or "lower is good" marker. It is a phenotype indicator. High values can mean genuine catecholamine excess (a tumor, acute cardiovascular stress, intense exposure-driven turnover) or reflect ongoing sympathetic overdrive from another cause. Low values can mean reduced sympathetic output (hypothalamic injury) or toxic suppression of metabolism. The same number means different things depending on context, which is why interpretation almost always requires pairing VMA with related markers and clinical history.

Reference Ranges

Cutpoints for VMA vary by lab and collection method, and most published thresholds come from 24-hour urine collections rather than the dried urine spot used by this test. The ranges below are illustrative orientation from the largest cohorts available, not a target. Your lab will likely report different numbers in different units, and the most reliable comparison is your own values within the same lab over time.

Source: Zeng et al. 2022 (n=491); Boyle et al. 2007 (n=159). Standardized clinical cutpoints for dried urine spot VMA do not yet exist, which is part of why this marker is best used to track your own trend rather than to make a single hard call.

When Results Can Be Misleading

A single VMA reading is sensitive to short-term factors that have nothing to do with disease:

• Recent intense exercise: in a study of 22 men, vigorous physical activity acutely raised noradrenaline output, which feeds the pathway VMA tracks. Levels normalize within hours.
• Acute illness or surgery: in a retrospective analysis of 7,834 hospitalized adults, urine catecholamine breakdown products in inpatients were often elevated to a degree that overlapped with values seen in catecholamine-secreting tumors. A reading taken while you are sick or recovering from a procedure should not be trusted as your baseline.
• Diet in the 24 to 72 hours before collection: in 26 healthy adults, a catecholamine-rich diet (foods like bananas, citrus, vanilla, and certain nuts) significantly raised urinary catecholamine markers and produced more false-positive screens. A separate study in 14 healthy adults showed that lemon intake measurably shifted urinary organic acids including VMA.
• Cold exposure: in 6 men, prolonged cold disrupted the normal circadian rhythm of VMA excretion, meaning the time of collection can pull values up or down depending on environment.

Some medications shift VMA without indicating any underlying tumor or disease, including certain antidepressants and sympathomimetics that change catecholamine handling, and stimulants that drive transient sympathetic activation. These do not mean you have the condition the test screens for; they mean the reading is unreliable while you take them. Coordinate any test timing with your prescriber.

Why One Reading Is Not Enough

VMA varies substantially day to day with stress, sleep, diet, and activity. A single elevated value is a signal to repeat the test under controlled conditions, not a diagnosis. Because a single sample captures only a day or two of sympathetic output, retesting matters: you are looking for a pattern, not a moment.

Get a baseline collection under your normal conditions. If a result is borderline or unexpected, repeat in 4 to 6 weeks after dialing in collection technique and a controlled pre-test diet. If you make targeted changes (reducing chronic stress load, addressing an environmental exposure, treating a tumor), retest at 3 to 6 months to see whether your trend has shifted. For long-term tracking, annual measurement gives you a stable longitudinal picture.

What to Do With an Abnormal Result

An elevated VMA is a reason to investigate, not panic. The standard next step is to add complementary tests that cover what VMA alone can miss:

• Plasma or urinary free metanephrines: the highest-sensitivity test for pheochromocytoma (100 out of 100 cases caught in one study), and the recommended primary screen if a tumor is suspected.
• Urinary HVA (homovanillic acid): a sister breakdown product that is often ordered alongside VMA, especially when neuroblastoma is being considered in a child.
• Plasma catecholamines: direct hormone levels that confirm whether elevated breakdown products reflect true overproduction.
• Imaging: if biochemical tests are convincing, abdominal MRI or CT is the next step to localize an adrenal tumor.

If your VMA is high and your metanephrines are normal, and you feel well, the most common explanation is short-term sympathetic activation or a pre-test confounder. Repeat the test under cleaner conditions. If VMA is high and metanephrines are also elevated, that combination is worth bringing to an endocrinologist or a clinician familiar with adrenal disease. A low VMA in someone who feels well rarely needs urgent action, but it can be worth pairing with other markers of autonomic function if you suspect chronically reduced sympathetic output.