Urine Tests for Neuroendocrine Tumors

Hydroxyindoleacetic acid (5-HIAA) urine test

Hydroxyindoleacetic acid (5-HIAA) is a breakdown product of the hormone serotonin. Neuroendocrine tumors can secrete this hormone. Since serotonin levels go up and down throughout a normal day, a 24-hour urine collection of the 5-HIAA byproduct is a more reliable measurement of daily amounts of the hormone. Your doctor may use the 5-HIAA test in diagnosing and monitoring neuroendocrine cancer.

Foods to avoid for 48 hours before a Hydroxyindoleacetic acid (5-HIAA) urine test:15

  • Avocados
  • Bananas
  • Cantaloupe
  • Eggplant
  • Grapefruit
  • Dates
  • Hickory nuts
  • Honeydew melon
  • Kiwi
  • Pecans
  • Pineapple
  • Plantains
  • Plums
  • Tomatoes and tomato products
  • Walnuts

There may also be prescription and over-the-counter medications to avoid before a 5-HIAA urine check. Make sure to get a complete list of foods and medications to avoid before the 5-HIAA test from your doctor.

Advice from patients on finding a NET specialist.

15National Comprehensive Cancer Network® (NCCN). NCCN Guidelines Neuroendocrine and Adrenal Tumors. (Version 3.2018) https://www.nccn.org/professionals/physician_gls/PDF/neuroendocrine.pdf. Accessed October 24, 2018