5-Hydroxyindoleacetic acid (5-HIAA)

🔬 What is 5-HIAA? Full name: 5-Hydroxyindoleacetic acid Produced from: The metabolism of serotonin (5-hydroxytryptamine or 5-HT) Excreted through: Urine 🧪 Test Name5-Hydroxyindoleacetic Acid (5-HIAA), Urine TestThis test measures how much 5-HIAA is present in the urine, usually collected over 24 hours.💡 Purpose of the TestThe test is mainly used to diagnose and monitor carcinoid tumors, which are rare tumors that can produce large amounts of serotonin.High serotonin levels lead to increased 5-HIAA in the urine.⚠️ When It’s OrderedA doctor might order the 5-HIAA test if a patient has symptoms suggestive of carcinoid syndrome, such as: Flushing (redness/warmth of skin) Diarrhea Wheezing or shortness of breath Rapid heartbeat Abdominal pain or cramping 📊 Normal Range (Typical Reference) Adults: 2 to 8 mg/24 hours (varies slightly by lab) (Note: Always check the specific lab’s reference range.)📈 High 5-HIAA Levels May Indicate Carcinoid tumors (especially of the gastrointestinal tract) Metastatic carcinoid cancer Rarely, conditions like: Malabsorption syndromes Celiac disease 🍌 Foods and Drugs Affecting Test ResultsCertain foods and medications can falsely increase or decrease 5-HIAA levels. You’ll usually be asked to avoid for 2–3 days before and during collection:Avoid foods rich in serotonin: Bananas 🍌 Pineapples 🍍 Tomatoes 🍅 Plums Avocados 🥑 Eggplant 🍆 Walnuts Avoid medications that interfere: Cough/cold medicines with guaifenesin Acetaminophen (paracetamol) Caffeine Levodopa MAO inhibitors Certain antidepressants 🧴 Sample Collection Specimen: 24-hour urine Container: Acid-preserved collection bottle Storage: Keep refrigerated during collection 🧠 Clinical Interpretation ResultPossible InterpretationNormalNo carcinoid activityMildly elevatedPossible dietary/drug interference or early carcinoidSignificantly elevatedStrongly suggests carcinoid tumor activity