24-Hour Urinary Vanillylmandelic Acid (VMA)

24-Hour Urinary Vanillylmandelic Acid (VMA) Test: Details & Precautions

The 24-hour urine VMA test measures vanillylmandelic acid (VMA), a metabolite of catecholamines (epinephrine and norepinephrine). This test helps diagnose pheochromocytoma, neuroblastoma, and other neuroendocrine tumors.

Test Details

✅ Purpose:

• Detects and diagnoses pheochromocytoma (tumor of adrenal glands).
• Identifies neuroblastoma (common childhood nerve tissue tumor).
• Evaluates hypertension (high blood pressure) linked to excess catecholamine production.
• Monitors treatment response for catecholamine-secreting tumors.

✅ Substances Measured:

• Vanillylmandelic Acid (VMA) – A breakdown product of epinephrine (adrenaline) and norepinephrine (noradrenaline).

✅ Normal Reference Range (May vary by lab):

• VMA levels: 1–7 mg/24 hours
• Higher levels may suggest pheochromocytoma, neuroblastoma, or stress-related conditions.

🔴 Elevated VMA Levels May Indicate:

• Pheochromocytoma (adrenal gland tumor).
• Neuroblastoma (common in children).
• Paraganglioma (rare neuroendocrine tumor).
• Chronic stress or stimulant use (caffeine, nicotine).
• Severe hypertension or kidney disease.

Precautions Before & During the Test

🔹 Before the Test

1️⃣ Dietary Restrictions (Avoid for 2–3 Days Before Test)

• Caffeinated drinks (coffee, tea, cola, energy drinks).
• Chocolate, bananas, avocados, citrus fruits, and vanilla (interfere with VMA levels).
• Alcohol and nicotine (avoid smoking, chewing tobacco, vaping).

2️⃣ Medication Restrictions (Check with doctor before stopping any medication)

• Beta-blockers, alpha-blockers (for high blood pressure).
• Decongestants (pseudoephedrine, phenylephrine).
• Antidepressants (MAOIs, SSRIs, tricyclics).
• Diuretics and corticosteroids.
• Levodopa (used for Parkinson’s disease).

3️⃣ Physical & Emotional Considerations

• Avoid strenuous exercise (can increase VMA levels).
• Stay calm and reduce stress.

🔹 During the Test

1️⃣ Urine Collection Procedure

• Use a clean container provided by the lab.
• Day 1 (Morning): Discard the first urine sample.
• Collect ALL urine for the next 24 hours.
• Day 2 (Morning): Include the first urine sample.

2️⃣ Proper Storage

• Refrigerate or keep on ice during collection.

3️⃣ Avoid Contamination

• Do not mix with stool, toilet paper, or other substances.

🔹 After the Test

• Return the sample to the lab as soon as possible.
• Results take a few days.
• If abnormal, additional tests like plasma catecholamines, MRI, or CT scan may be needed.