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

The 5-Hydroxyindoleacetic Acid (5-HIAA), 24-Hour Urine test contains 1 test with 3 biomarkers.

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

Patient Preparation: Patient should avoid food high in indoles: avocado, banana, tomato, plum, walnut, pineapple, and eggplant.

Collection Instructions : Collect 24-hour urine with 6N HCL to maintain a pH below 3. Urine without preservative is acceptable if pH is below 6 and the sample is shipped frozen. Keep urine refrigerated during collection if preservative is not used. Shipping refrigerated acceptable, shipping frozen acceptable. Record 24-hour urine volume on test request form and urine vial. Record patient's age on test request form and urine vial.

Clinical Significance: 5-HIAA is the end product of serotonin (5-hydroxytryptophan) and tyrptophan 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.

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.

The following is a list of what is included in the item above. Click the test(s) below to view what biomarkers are measured along with an explanation of what the biomarker is measuring.

5-HIAA, Urine

Creatinine, Urine

Total Volume

*Process times are an estimate and are not guaranteed. The lab may need additional time due to weather, holidays, confirmation/repeat testing, or equipment maintenance.

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