5-Hydroxyindoleacetic Acid (5HIAA) 24 Hour Urine Test

5-Hydroxyindoleacetic acid (5-HIAA) is the major metabolite of serotonin.

Increased amount are found in intestinal carcinoid tumors and neuroendocrine tumors, especially when carcinoid syndrome is present.

Carcinoid syndrome is characterized by serotonin producing tumors, flushing, heart problem, and some degree of hepatomegaly.

Normal Reference Range

2-10 years < 8.0 mg/d
> 10 years  < 6.0 mg/d

Test Useful For

Elevated excretion of 5-HIAA is one of the indicators of the presence of a serotonin-producing tumor. So, this test is used for diagnosis and monitoring of intestinal carcinoid syndrome.

Precautions

Food with a high content of serotonin (avocados, bananas, plums, walnuts, pineapple, eggplant, tomatoes, kiwifruit, dates, grapefruit, nuts, cantaloupe and some medicines which increase serotonin release) should be avoided within 48 hours of the urine collection.

These can falsely elevate 5-hydroxyindoleacetic acid (5-HIAA) excretion.

5-Hydroxyindoleacetic Acid (5-HIAA) Lab Report Checker