Serotonin, Serum

Also Known As: 5-HT, Serum; 5-HT; 5-Hydroxytryptamine, Serum; 5-Hydroxy Tryptamine;

Methodology: High-pressure liquid chromatography (HPLC) with electrochemical (EC) detection

Preparation: No fasting required. Avoid food high in indoles such as avocado, banana, tomato, plum, walnut, pineapple, and eggplant. Tobacco, tea and coffee should also be avoided three days prior to specimen collection. Serotonin levels may be affected by certain types of medications such as morphine, MAO inhibitors, methyldopa, and lithium. Check with physician before stopping any medications.

Note:

This test is not an accurate determinant for neurological levels of serotonin. This is relative to gut production.

Serotonin (5-hydroxytryptamine) is synthesized from the essential amino acid tryptophan via the intermediate 5-hydroxytryptophan (5-HTP).

Serotonin release from the intestines causes activates digestive tract motility, and blood flow. Most is utilized by the lungs and liver where it is broken down to 5-HIAA, which is a metabolite found in the urine and best used for testing elevations of systemic serotonin, often caused by carcinoid tumors. The modest levels of serotonin that are not metabolized by the liver or lungs are absorbed by platelets, which use the compound to help with clotting.