5-Hydroxyindoleacetic Acid (5-HIAA), 24-Hour Urine, with Creatinine

Test Code

5HI24

Alias/See Also

39625

CPT Codes
83497, 82570

Includes

CPT code 81050 may be added at an additional charge for volume measurement

Preferred Specimen

10 mL of a 24-hour urine, preserved with 25 mL 6N HCl collected in a plastic, 24-hour urine container

Minimum Volume

5 mL

Other Acceptable Specimens

10 mL of a 24-hour urine, unpreserved, with a pH ≤ 6, collected in a plastic, 24-hour urine container

Instructions

Collect 24-hour urine with 25 mL 6N HCl to maintain a pH ≤ 3. If no preservative is used, specimen must be stored refrigerated during collection but shipped frozen and pH must be > 6. Record 24-hour urine volume and patient's age on test request form and on urine container.

Transport Temperature

Preserved urine: Room temperature
Unpreserved urine: Frozen

Specimen Stability

Preserved urine
Room temperature: 7 days
Refrigerated: 30 days
Frozen: 30 days

Unpreserved urine
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Preserved urine received refrigerated with a pH >3 • Unpreserved urine received frozen with pH >6

Methodology
High Performance Liquid Chromatography (HPLC) • Electrochemical Detection

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Tuesday-Saturday Morning Report available: 2 Days after receipt at the performing laboratory. Add three (3) days for transport.

Limitations

Patients with renal disease may display falsely decreased results. Urinary 5-HIAA is increased in patients with malabsorption disorders who also display a larger concentration of urinary tryptophan metabolites. Urinary 5-HIAA is increased in patients with intestinal obstruction and with some noncarcinoid islet cell tumors. Carcinoid syndrome may not cause elevated results, especially if the patient does not have diarrhea.

Reference Range

See Laboratory Report

Clinical Significance

5-HIAA is the end product of serotonin (5-hydroxytryptophan) and tryptophan metabolism. Patients with carcinoid tumors of the midgut, e.g., ileum, produce high concentrations of 5-HIAA. Patients with carcinoid tumors of the foregut and hindgut may produce little or no 5-HIAA or do so intermittently.

Performing Laboratory

Quest Diagnostics Nichols Institute-San Juan Capistrano, CA

33608 Ortega Highway

San Juan Capistrano, CA 92675-2042

Last Updated: August 4, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.