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Test Name:
5-Hydroxyindoleacetic Acid, Quantitative, Urine, 24-Hour
- SBMF No:
23236 - Performance Lab Name:
Manual Lab - Test Mnemonic:
U 5HIAA-24 - ABN:
Not required - CPT Code:
83497 - LOINC Code:
31203-3; 1695-6; 3167-4; 13362-9; 20624-3; 2162-6; 19150-2 - Test Includes:
5-Hydroxyindoleacetic Acid, 24-Hour Urine
Creatinine, 24-Hour Urine - Also Known As:
5-HIAA
Serotonin metabolite - Also See:
23238 5-Hydroxyindoleacetic Acid, Quantitative, Urine, Random - Spec Type:
Urine, 24-hour - Spec Container:
Plastic container with tightly fitting lid (no preservative) - Pref Vol:
10.0 mL - Min Vol:
4.0 mL - Fasting:
No - Patient Prep:
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 - Spec Collect:
To begin collection of timed specimen, have patient urinate, noting date and exact time
Discard this first portion of urine, but document date and time of voiding on container label and test requisition as "start" of timed specimen
Save all urine voided during designated time period, including portion voided at exact end of time period
IMPORTANT: Refrigerate entire specimen (2-8°C) during and after collection to prevent bacterial growth
Document date and time of final voiding on label and requisition as "end" of timed specimen - Spec Process:
Upon completion of collection, mix entire specimen well and measure total 24-hour volume
Pour off 10.0 mL of urine into separate plastic tube
Immediately transport refrigerated aliquot with notation of total 24-hour urine volume on aliquot label and requisition - Spec Store Transport:
Refrigerated - Spec Stability:
1 week refrigerated (2-8°C) - Spec Reject:
Addition of HCl to urine sample is cause for rejection - Methodology:
High Performance Liquid Chromatography (HPLC) - Use:
Diagnosis of carcinoid tumors - Clinical Significance:
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. - Reference Range:
0.7–8.2 mg/day
Levels greater than 25 mg/day suggest the presence of a serotonin excreting tumor - Day Run:
Wed, Sat - Time Run:
7:00 am - Time Reported:
5:00 pm - Test Type:
HORMONE
