5ohindoleacetate24hurql
A 24-hour urine test that measures 5-hydroxyindoleacetate (5-HIAA), a breakdown product of serotonin, to help detect carcinoid tumors and other conditions.
{"This test measures serotonin breakdown products in your urine collected over 24 hours","It helps doctors diagnose carcinoid tumors, which are rare neuroendocrine growths","Avoid certain foods (bananas, avocados, nuts) and medications for 3 days before collection","All urine must be collected for 24 hours for accurate results","Results help your healthcare provider check for tumors that produce excess serotonin"}
Key facts at a glance
- LOINC
- 12172-3
- Short code
- 5HIAA24
- Synonyms
- 5OH-indoleacetate 24h Ur Ql
- Category
- chemistry
- Sample
- urine
- Container
- 24-hour urine collection container with appropriate preservative (typically 10% HCl or acetic acid) or sterile plastic container
- Units
- N/A
- Ref low
- 20
- Ref high
- 400
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- High Performance Liquid Chromatography (HPLC) with Electrochemical Detection or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 83497
- SNOMED
- 39355001
- Specimen volume
- Aliquot of 10-20 mL from well-mixed 24-hour urine collection
- Stability
- Room temperature: 24-48 hours; Refrigerated (2-8°C): 5-7 days; Frozen (-20°C or below): 30 days. Protect from light.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The 5-Hydroxyindoleacetate (5-HIAA) test measures the amount of this substance in your urine over a 24-hour period. 5-HIAA is a waste product created when your body breaks down serotonin, a hormone and neurotransmitter that helps regulate mood, sleep, and other functions. This test helps doctors check if your body is producing abnormal amounts of serotonin.
Why do I need this test?
Your doctor may order this test if they suspect you have a carcinoid tumor. These are rare, slow-growing tumors that can develop in various parts of the body, commonly in the digestive system or lungs. Carcinoid tumors can produce excess serotonin, leading to higher levels of 5-HIAA in your urine. Symptoms that might prompt this test include facial flushing, diarrhea, abdominal pain, or unexplained weight loss.
How do I prepare for the test?
For 3 days before and during the urine collection, you must avoid certain foods that are high in serotonin or tryptophan, including bananas, avocados, pineapples, plums, walnuts, and certain cheeses. You should also avoid alcohol, caffeine, and certain medications such as antidepressants, cough medicines, and pain relievers. Always tell your doctor about all medications and supplements you are taking. Follow any specific instructions provided by your healthcare team.
How is the test performed?
You will receive a special container for collecting your urine. On the morning of collection, start by urinating into the toilet and note the time. For the next 24 hours, collect all urine in the provided container. Keep the container refrigerated or in a cool place. At the end of 24 hours, urinate one final time and add that sample to the container. Return the container to your lab or healthcare provider as instructed.
What do the results mean?
Normal 5-HIAA levels vary by laboratory, but results are typically reported as milligrams per 24 hours (mg/24h). Elevated levels may indicate the presence of a carcinoid tumor. Your doctor will interpret your results based on your symptoms, medical history, and other test findings. A single abnormal result does not always mean you have a tumor; your doctor may order additional tests to confirm a diagnosis.
Reference range
Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A
Patients should avoid foods rich in serotonin for 48-72 hours before and during collection: bananas, pineapples, walnuts, avocados, eggplant, tomatoes, and plums. Avoid medications that may interfere: antidepressants (SSRIs, MAOIs), levodopa, methyldopa, and reserpine. Instruct patient to collect urine for exactly 24 hours, discarding first morning specimen and including the final morning specimen. Keep container refrigerated or on ice during collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings2
Frequently asked questions
Is the 24-hour urine collection uncomfortable?
What happens if I miss a urine sample during the 24-hour period?
Can I take my regular medications during the test?
How long will it take to get my results?
What if my results are abnormal?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy