5‑Hydroxyindoleacetic Acid (5‑HIAA), 24‑Hour Urine without Creatinine
Use
This test measures the 24‑hour excretion of 5‑hydroxyindoleacetic acid (5‑HIAA), a serotonin metabolite, useful for the biochemical diagnosis and monitoring of carcinoid syndrome and related conditions. Elevated 5‑HIAA levels may indicate increased serotonin production, which is characteristic of carcinoid tumors.
Special Instructions
Not provided.
Limitations
Specimen rejection occurs if urine pH exceeds 3.0 when received unfrozen. Urine without preservative is acceptable only if pH is below 6 and the sample is shipped frozen. Improper diet or medication use may result in falsely elevated levels.
Methodology
Other
Biomarkers
5‑Hydroxyindoleacetate
AnalyteTotal Volume
Analyte
LOINC Codes
- 1695-6 - 5OH-indoleacetate 24h Ur-mRate
- 3167-4 - Specimen vol 24h Ur
Result Turnaround Time
2 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
10 mL (5 mL minimum)
Minimum Volume
Not provided
Container
24‑hour urine container
Collection Instructions
Collect 24‑hour urine in container with 25 mL of 6 N HCl to maintain pH < 3. If preservative not used and pH ≤ 6, specimen must be shipped frozen. Keep refrigerated during collection if unpreserved. Record 24‑hour volume and patient age on container and requisition.
Patient Preparation
Avoid foods high in indoles (avocado, banana, tomato, plum, walnut, pineapple, eggplant) and avoid tobacco, tea, and coffee prior to and during collection.
Causes for Rejection
pH > 3.0 and received unfrozen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 30 days |
| Frozen | 30 days |
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