Serotonin

Norm
570–1700 nmol/L

Synonyms: 5-HT, 5-hydroxytryptamine.
Plasma EDTA
Purple top

A rarely performed test. In cases of unclear diagnosis, serotonin testing is used to diagnose carcinoid syndrome (APUD tumors). Classic symptoms of carcinoid syndrome: vasomotor instability (blood pressure, pulse), diarrhea, hepatomegaly, endocardial damage, facial flushing symptoms. Carcinoid tumors are a manifestation of multiple endocrine neoplasias. Tumors capable of producing serotonin: lungs, thyroid, pancreas, intestines, stomach, ovaries. Typically, patients with increased serotonin concentrations have liver metastases. For the diagnosis of carcinoid syndrome and better monitoring, a more sensitive and specific test is urine 5-HIAA.

Source | Handbook of Basic Laboratory Tests | Doctor of Medical Sciences Gintaras Zaleskis