5-hydroxyindoleacetate (5HIAA) is a metabolite of serotonin and is excreted in the urine. Serotonin is produced in large amounts by carcinoid tumors. Carcinoid tumors are rare, slow-growing tumors usually found in the lining of the digestive tract or in the lungs. The serotonin that is released by the carcinoid tumors is metabolized by monoamine oxidase in the liver, lungs, and brain to 5HIAA. Testing for elevated levels of 5HIAA in 24 hour urine specimens is 73% sensitive and 100% specific for the diagnosis of carcinoid tumors. A fasting plasma 5HIAA correlates to a urine 5HIAA and other relevant biomarkers. A significantly increased level of 5-HIAA in a 24-hour urine sample in a person with carcinoid syndrome symptoms is suggestive but not diagnostic of a carcinoid tumor.
Inform your doctor if you are on any medications, have any allergies or underlying medical conditions before your 5 Hiaa 24 Hour Urine. Your doctor will give specific instructions depending on your condition on how to prepare for 5 Hiaa 24 Hour Urine.
Your doctor will ask you to stop certain foods and medications that alter 5HIAA 72 hrs before testing.
| Gender | Age groups | Value |
| UNISEX | All age groups | 2 - 7mg/24hr |