5-HIAA,QUANTITATIVE 24 HOUR URINE
- 5-HIAA,QUANTITATIVE 24 HOUR URINE
- Start Date
- Expiration Date
- Serotonin Metabolite (Quantitative); HIAA (Quantitative); Hydroxyindoleacetic Acid (Quantitative)
- CPT Codes
- Reference Test
- Transport Info
- Fasting Required?
- Patient Instructions
For 72 hours prior to and during collection, observe the following restrictions:
Dietary: avoid avocados, bananas, eggplant, pineapple, plums, tomatoes, or walnuts.
Other: avoid medications, over-the-counter drugs, or herbal remedies.
- Reference Range
Levels greater than 25 mg/day suggest the presence of a serotonin excreting tumor
High Performance Liquid Chromatography (HPLC)
Carcinoids are the most common tumors arising from the diffuse neuroendocrine system of the GI tract and pancreas. As with normal gut endocrine cells, carcinoids synthesize, store, and release a variety of hormones and biogenic amines. Serotonin is one of the best characterized among these substances.
Overproduction of serotonin is found in 90 to 100% of patients with carcinoid syndrome. Measurement of serotonin and its metabolites in body fluid and tissue is important in the evaluation of this syndrome. Serotonin is converted to the metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and is excreted by the kidneys. As a result, urinary determination of 5-HIAA is the most frequently used test for the diagnosis of carcinoid syndrome.
In pathological conditions, 5-HIAA is excreted in very large amounts, often exceeding 350 mg/day. However, it is critical to use a more sensitive 5-HIAA method for early diagnosis when tumors are small and not metastasized. 5-HIAA excretion values of these tumors barely exceed 8 mg/day. SBMF is replacing the previous qualitative method with a new, more sensitive, quantitative method for 5-HIAA.