5 Hydroxyindoleacetic Acid Test (5 HIAA) – Why am I having this test?
5 Hydroxyindoleacetic Acid Test is a 24-hour urine collection test that measures a product of serotonin called 5 HIAA. This test is done to check the amount of 5-HIAA that your body is removing.
This test helps to detect some types of tumors (carcinoid tumors) and certain other medical conditions. This test is also used to monitor the treatment of carcinoid tumors.
What kind of sample is taken?
A urine sample is collected in a sterile container that will be given to you by the lab to use at home before the test.
How do I collect samples at home?
You will be asked to collect a urine sample at home over a period of 24 hours. Follow your health care provider’s instructions about how to collect and store your sample.
How do I prepare for this test?
Before the test, you will need to avoid certain foods, alcohol, prescriptions, and over-the-counter medications. Ask your health care provider how long you should follow these instructions before taking the test:
- Do not eat foods that contain the hormone serotonin. This includes foods such as bananas, plantains, pineapple, kiwi, walnuts, plums, pecans, eggplant, tomatoes, and avocados. Do noteat those foods while taking the test either.
- Do not drink alcohol.
- Do not take prescriptions and over-the-counter medicines that interfere with the test. Ask your health care provider about changing or stopping your regular medicines.
What are the reference ranges?
Reference ranges are considered healthy ranges established after testing a large group of healthy people. Reference ranges may vary among different people, labs, and hospitals. It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.
What do the results mean?
The reference range for this test is 2–8 mg in a 24-hour period or 10–40 micromoles per day (SI units).
Increased levels of 5-HIAA may indicate:
- The presence of a carcinoid tumor.
- Cystic fibrosis.
- Noncarcinoid illness.
- Intestinal malabsorption.
If you already have a carcinoid tumor, an increased level of 5-HIAA may also indicate that your treatment is not working.
Decreased levels of 5-HIAA may indicate:
- Depression.
- Migraine.
If you already have a carcinoid tumor, a decreased level of 5-HIAA may also indicate that your treatment is working.
Talk with your health care provider to discuss your results, treatment options, and if necessary, the need for more tests. Talk with your health care provider if you have any questions about your results.
Talk with your health care provider to discuss your results, treatment options, and if necessary, the need for more tests. Talk with your health care provider if you have any questions about your results.
