5-Hydroxyindoleacetic acid (synonyms: 5-HIES, HIES) is a metabolic product formed by the breakdown of serotonin.
The process
Material needed
- 24 h urine
- Prepare collection vessel beforehand with 12 ml hydrochloric acid
Preparation of the patient
- The following substances must not be taken for three days before the diagnostic procedure:
- Fruits such as pineapples, bananas, currants, kiwis, melons, mirabelles, plums, gooseberries, plums.
- Vegetables such as eggplant, avocados, tomatoes.
- Nuts such as pecans, walnuts
- Cheese
- Cocoa
- Drugs: chlorpromazine, methamphetamine, methocarbamol, mephenescincarbamate, reserpine.
- Coffee and nicotine can also lead to falsified results
Interfering factors
- None known
Normal value
Normal value in mg/24 h | < 9 |
- Values > 40 mg/24 h are probative of a carcinoid
Indications
- Suspected ileal carcinoid (serotonin-producing neuroendocrine neoplasms (NEN); serotonin-producing NEN).
Interpretation
Interpretation of increased values
- Epilepsy
- Carcinoids (synonyms: diffuse neuroendocrine neoplasia (neoplasm); neuroendocrine tumors, NET; gastoenteropancreatic neuroendocrine neoplasia (GEP-NEN)). – Localization: Depending on the localization, the following are distinguished: bronchus carcinoid, thymus carcinoid, appendix carcinoid, ileum carcinoid, duodenal carcinoid, gastric carcinoid, rectum carcinoid (colon NET), pancreas carcinoid (pancreas NET); about 80 percent of the tumors are localized in the terminal ileum or appendix.Symptoms: The first sign is often a persistent diarrhea. Typical for the carcinoids (GEP-NEN) is the “flush symptomatology” (flush syndrome); this is a sudden blue-red discoloration of the face, neck and under certain circumstances of the torso understood, furthermore hypoglycemias (hypoglycemia) or duodenal ulcers (ulcers of the duodenum).
- Celiac disease (gluten-induced enteropathy) – chronic disease of the mucosa of the small intestine (small intestinal mucosa), which is based on hypersensitivity to the cereal protein gluten.
Interpretation of lowered values
- Not relevant to the disease
Further notes
- In the symptom-free interval of a carcinoid, the HIES may be unremarkable! (If clinical suspicion is urgent, repeat examination is indicated!).