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HelpTest Code HIAAP 5-Hydroxyindoleacetic Acid, Plasma
Ordering Guidance
This test quantifies 5-hydroxyindoleacetic acid in plasma specimens and is comparable to testing on 24-hour and random urine specimens for the diagnosis and monitoring of intestinal carcinoid syndrome.
Necessary Information
Patient's age is required.
Specimen Required
Patient Preparation:
1. Some medications could interfere with test results. The ordering provider should decide if any medications should be stopped and when they should be restarted. If clinically feasible, discontinue the following medications at least 24 hours prior to specimen collection:
-Acetaminophen (Tylenol or generic versions)
-Tryptophan containing supplements.
2. For 24 hours prior to the collection, the patient should:
Limit the following to one serving per day:
-Fruits
-Vegetables
-Caffeinated beverages or foods
Abstain from the following:
-Nuts, especially walnuts. Plasma 5-hydroxyindoleacetic acid levels revert to baseline levels when walnuts are ingested after other foods.
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Centrifuge at 4° C.
2. Aliquot plasma into plastic vial.
3. Send plasma frozen.
Useful For
Biochemical diagnosis and monitoring of intestinal carcinoid syndrome using a plasma specimen
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
5-Hydroxyindoleacetic Acid, PSpecimen Type
PlasmaSpecimen Minimum Volume
0.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma | Frozen (preferred) | 60 days | |
| Refrigerated | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Thawing** | Cold OK; Warm reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Intestinal carcinoid and neuroendocrine tumors can produce excess amounts of serotonin and its degradation product, 5-hydroxyindoleacetic acid (5-HIAA). Determination of 5-HIAA in urine or plasma is used to diagnose and monitor patients with carcinoid syndrome.
Carcinoid syndrome is characterized by a constellation of hormonal symptoms such as abdominal pain, increased bowel movements, episodic facial flushing, bronchoconstriction, venous telangiectasia, niacin deficiency-related symptoms, and long-term complications, such as mesenteric fibrosis and carcinoid heart disease.(1)
Measurement of 5-HIAA in a plasma specimen can diagnose carcinoid disease and produces comparable results to urinary 5-HIAA testing.
Reference Values
≤6 months: ≤130 ng/mL
>6 months: ≤30 ng/mL
Interpretation
If pharmacological and dietary artifacts have been ruled out, an elevated concentration of 5-hydroxyindoleacetic acid is a probable indicator of the presence of a serotonin-producing tumor.
Cautions
Intake of food with a high content of serotonin (avocados, dates, eggplant, all fruit [including bananas, cantaloupe, grapefruit, kiwifruit, melons, pineapple, plantains, plums], all nuts [including walnuts, hickory nuts, butternuts, pecans], and tomatoes and tomato products) within 24 hours of the plasma collection could result in falsely elevated 5-hydroxyindoleacetic acid (5-HIAA) excretion.
Numerous drugs affect the excretion of 5-HIAA by different mechanisms, including increased serotonin synthesis, metabolism, and release and inhibition of uptake. The following medications can interfere with 5-HIAA results.
-Acetaminophen (Tylenol or generic versions)
-Tryptophan containing supplements
Method Description
Plasma is mixed with deuterium labeled hydroxyindoleacetic acid (HIAA) as internal standard in acetonitrile. After centrifugation and filtration, the sample is reconstituted in mobile phase. Liquid chromatography tandem mass spectrometry is performed by injecting the reconstituted specimen onto a reverse phase high-performance liquid chromatography column. HIAA is quantitated using the stable isotope-labeled internal standard from calibration over a concentration range of 0 to 1000 ng/mL.(Unpublished Mayo method)
Day(s) Performed
Monday, Wednesday, Friday
Report Available
3 to 6 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83497
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HIAAP | 5-Hydroxyindoleacetic Acid, P | 1693-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 619735 | 5-Hydroxyindoleacetic Acid, P | 1693-1 |