📌 What is this test?
The 5-HIAA test measures the amount of 5-hydroxyindoleacetic acid, a breakdown product of serotonin, in the urine. It is commonly used to help diagnose and monitor carcinoid tumors, which can produce excess serotonin.
📌 Purpose of the Test
✅ Detect and monitor carcinoid syndrome
✅ Identify serotonin-producing tumors
✅ Evaluate flushing, diarrhea, and heart issues caused by carcinoid tumors
✅ Assess serotonin metabolism in certain disorders
📌 Normal Ranges
2 to 9 mg per 24 hours (may vary by lab)
📌 What can affect the levels?
🔼 Increased Levels:
✔️ Carcinoid tumors
✔️ High serotonin-producing foods (bananas, pineapples, walnuts, avocados, etc.)
✔️ Certain medications (e.g., SSRIs, L-Dopa)
🔽 Decreased Levels:
❌ Use of certain medications (aspirin, MAO inhibitors)
❌ Malabsorption disorders
📌 Preparation & Testing
24-hour urine collection is required
Avoid serotonin-rich foods (bananas, tomatoes, coffee, chocolate, etc.) before the test
Stay hydrated and follow your doctor's instructions