Additional Testing Requirements

First-line testing for the diagnosis of carcinoid tumors with symptoms suggestive of carcinoid syndrome consists of urinary serotonin (this test), urinary 5-HIAA (HIAA / 5-Hydroxyindoleacetic Acid [5-HIAA], 24 Hour, Urine), and serum chromogranin A (CGAK / Chromogranin A, Serum).

Necessary Information

24-Hour volume (in milliliters) is required.

Specimen Required

Patient Preparation:

1.Patients should not eat avocados, bananas, butternuts, cantaloupe, dates, eggplant, grapefruit, hickory nuts, honeydew melon, kiwifruit, melon, nuts, pecans, pineapple, plantains, plums, tomatoes, or walnuts, which are high in serotonin for 48 hours before and during collection.

2. Patient should discontinue medications that may elevate urine serotonin concentration including lithium, monoamine oxidase-inhibitors, methyldopa, morphine, and reserpine. Patient should also discontinue use of selective serotonin reuptake inhibitors (SSRI; eg, PROZAC) that can lead to depletion of platelet serotonin levels and result in false-negative urine serotonin tests.

3. Patient should avoid heavy nicotine consumption during the 24-hour collection period.

Supplies: Urine Tubes, 10mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 5 mL

Collection Instructions:

1. Add 25 mL of 50% acetic acid as preservative at start of collection.

2. Collect urine for a full 24 hours (required) and record the total volume.

3. Refrigerate specimen during collection.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.