Skip to main content
An official website of the United States government
Español
Government Funding Lapse
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

5-hydroxyindoleacetic acid

(5-hy-DROK-see-IN-dole-uh-SEE-tik A-sid)
A substance formed by the breakdown of a hormone called serotonin in the liver. Nerves use serotonin to send messages to one another. After 5-hydroxyindoleacetic acid is broken down from serotonin in the liver, the kidneys filter it from the blood and pass it into the urine. Serotonin and 5-hydroxyindoleacetic acid may be found in higher-than-normal amounts in patients with certain tumors, such as carcinoid tumor. Measuring the amount of 5-hydroxyindoleacetic acid in the urine may help diagnose and monitor carcinoid tumors and other conditions. 5-hydroxyindoleacetic acid is a type of tumor marker. Also called 5-HIAA.
Search NCI's Dictionary of Cancer Terms