Type of test Urine (24-hour)

Normal findings

 2-8 mg/24 hr or 10-40 μmol/day (SI units)

Female levels lower than male levels

Test explanation and related physiology

Quantitative analysis of urine levels of 5-HIAA is used to detect and follow the clinical course of patients with carcinoid tumors. Carcinoid tumors are serotonin-secreting tumors that may grow in the appendix, intestine, lung, or any tissue derived from the neuroectoderm. These tumors contain argentaffin staining (enteroendocrine) cells, which produce serotonin and other powerful neurohormones that are metabolized by the liver to 5-HIAA and excreted in the urine. These powerful neurohormones are responsible for the clinical presentation of carcinoid syndrome (bronchospasm, flushing, diarrhea).

Interfering factors

 • Foods as listed below in Procedure and patient care

* Drugs that may cause increased 5-HIAA levels include acetaminophen, acetanilid, acetophenetidin, glyceryl guaiacolate, methocarbamol, and reserpine.

*  Drugs that may cause decreased levels include aspirin, chlorpromazine, ethyl alcohol, heparin, imipramine, isoniazid, levodopa, monoamine oxidase inhibitors, methenamine, methyldopa, phenothiazines, promethazine, and tricyclic antidepressants.

Procedure and patient care

 • See inside front cover for Routine Urine Testing for 24-hour collection.

* Instruct the patient to refrain from eating foods containing serotonin (e.g., plums, pineapples, bananas, eggplant) for several days before and during testing.

 • Keep the specimen on ice or in a refrigerator during the 24-hour collection. A preservative is needed.

Abnormal findings

 Increased levels

- Carcinoid tumors

- Noncarcinoid illness

- Cystic fibrosis

- Intestinal malabsorption

Decreased levels

- Mental depression

- Migraine headaches

مواضيع ذات صلة

Lipid Profile

17-hydroxycorticosteroids (17-OCHS)

Diagnosis of Dyslipidemia

Familial Hypercholesterolemia

human T-cell lymphotropic virus (HTLV) I/II antibody

human placental lactogen (hPL, Human chorionic somatomammotropin [HCS])

human papillomavirus (HPV test, HPV DNA testing, HPV Genotyping, HPV mRNA testing)

human lymphocyte antigen B27 (HLA-B27 antigen, Human leukocyte A antigen, White blood cell antigens, Histocompatibility leukocyte A antigen)

Nucleic Acid –Based Tests

human chorionic gonadotropin (hCG, Pregnancy tests, hCG beta subunit)

homocysteine (Hcy)

HIV serologic and virologic testing