5-HIAA (Serotonin Metabolite) 24-Hour Urine

• If you are experiencing episodes of facial flushing that may be accompanied by warmth and redness.
• If you have chronic, unexplained diarrhea that is not related to diet or infection.
• If a healthcare provider suspects you may have a neuroendocrine tumor, especially a carcinoid tumor.
• If you are being monitored after a diagnosis of a serotonin-producing tumor.

• Individuals experiencing symptoms commonly associated with carcinoid syndrome, such as unexplained flushing, persistent diarrhea, abdominal pain, or wheezing.
• Patients undergoing evaluation for neuroendocrine tumors (NETs), particularly those suspected of secreting serotonin.
• Those being monitored for the effectiveness of treatment for serotonin-producing tumors.

The 5-HIAA test is a primary diagnostic tool and monitoring marker for neuroendocrine tumors (NETs), particularly those of the gastrointestinal tract and lungs, which may secrete excessive amounts of serotonin. It is commonly used for:

• Diagnosing carcinoid syndrome, which is characterized by a collection of symptoms such as recurrent flushing of the skin, chronic diarrhea, abdominal cramping, and wheezing. These symptoms are often caused by the release of serotonin and other vasoactive substances by carcinoid tumors.
• Monitoring treatment effectiveness in patients with known serotonin-secreting tumors.
• Screening individuals with a strong suspicion of NETs based on persistent, unexplained symptoms that align with carcinoid syndrome.

It's important to discuss your test results with a healthcare provider. Levels of 5-HIAA can be influenced by certain foods, medications, and other medical conditions. A single test result may not provide a complete picture, and your doctor will interpret it in the context of your symptoms, medical history, and other diagnostic findings.