Biochemistry, 5 Hydroxyindoleacetic Acid

Excerpt

5-Hydroxy indoleacetic acid (5-HIAA) is the primary metabolite of serotonin. Serotonin is broken down into 5-hydroxy indoleacetic acid within the liver. 5-hydroxy indoleacetic acid is used as a proxy for serotonin measurement through a 24-hour urine test. 5-hydroxy indoleacetic acid's primary use is in diagnosing and monitoring carcinoid tumors, a subset of serotonin secreting neuroendocrine tumors.