Useful for biochemical diagnosis and monitoring of intestinal carcinoid syndrome
Specimen Type
24-Hour Urine
Specimen Collection / Processing Instructions
Patient Preparation:
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 48 hours prior to beginning collection until collection is complete:
Acetaminophen (Tylenol or generic versions)
Aspirin
Antihistamines
Cough syrups
Cold and flu medications
For 48 hours prior to beginning collection until collection is complete, the patient should limit intake of the following to one serving per day:
Fruits
Vegetables
Nuts
Caffeinated beverages or foods
Collection Instructions:
Collect a 24-hour urine specimen
Add 25 mL of 50% acetic acid as preservative at start of collection
Use 15 mL of 50% acetic acid for children <5 years old.
The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Limitations
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 hickory nuts, butternuts, pecans, walnuts], and tomatoes and tomato products) within 48 hours of the urine 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)
Aspirin
Antihistamines -Cough syrups
Cold and flu medications
Patient should also avoid caffeinated beverages such as tea and coffee or caffeinated foods for 48 hours before and during specimen collection.
Methodology
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
