24-Hour Urine Catecholamines

24-Hour Urine Catecholamines Test: Details & Precautions

The 24-hour urine catecholamines test measures the levels of catecholamines (dopamine, norepinephrine, epinephrine) and their metabolites (metanephrines, vanillylmandelic acid – VMA) in urine. It helps diagnose conditions related to excessive catecholamine production, such as pheochromocytoma, neuroblastoma, and other adrenal gland disorders.

Test Details

✅ Purpose:

• Detects pheochromocytoma (adrenal gland tumor).
• Diagnoses neuroblastoma (nerve tissue tumor).
• Evaluates hypertension (high blood pressure) caused by excess catecholamines.
• Monitors treatment response for catecholamine-related conditions.

✅ Hormones Measured:

1. Epinephrine (Adrenaline) – Controls “fight or flight” response.
2. Norepinephrine (Noradrenaline) – Regulates blood pressure and stress response.
3. Dopamine – Important for brain and kidney function.
4. Metanephrines & Vanillylmandelic Acid (VMA) – Breakdown products of catecholamines.

✅ Normal Reference Ranges (may vary by lab):

• Epinephrine: <20 µg/day
• Norepinephrine: 15–80 µg/day
• Dopamine: 65–400 µg/day
• Metanephrines: <1.3 mg/day
• VMA: 1–7 mg/day

🔴 Elevated Levels May Indicate:

• Pheochromocytoma (Adrenal Tumor)
• Neuroblastoma (Pediatric Cancer)
• Severe Hypertension (Catecholamine-related)
• Stress, Anxiety, or Intense Physical Activity
• Stimulant Drug Use (Caffeine, Nicotine, Cocaine, Amphetamines)

Precautions Before & During the Test

🔹 Before the Test

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

• Caffeinated drinks (coffee, tea, cola, energy drinks).
• Chocolate, bananas, avocados, citrus fruits, and vanilla (can interfere with results).
• Alcohol and nicotine (no smoking, chewing tobacco, or vaping).

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

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

3️⃣ Physical & Emotional Factors (Avoid Before & During Test)

• Intense exercise (raises catecholamine levels).
• Stress or emotional distress (try to stay calm).

🔹 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 the sample on ice at all times.

3️⃣ Avoid Contamination

• Do not mix urine 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 ordered.