Serotonin Level, Blood Test



Quest Diagnostics Test Code: 29851

Serotonin is a chemical with the function of being a chemical messenger in the central nervous system. It can also be found in other places in the body, like platelets. This chemical is responsible for wake-sleep cycles and maintaining mood. It is broken down in the liver to its metabolites which are eliminated in the urine. This blood test measures the amount of serotonin in the blood, primarily used for the diagnosis of carcinoid tumors. These cancers arise from the neuroendocrine system.

This blood test is performed in following conditions such as:

• Flushing of the face and neck
• Diarrhea
• Nausea and vomiting
• Rapid heart rate
• Wheezing, coughing
• Difficulty breathing

Also Known As: 5-Hydroxytryptamine, 5-HT


Avoid food high in indoles such as avocado, banana, tomato, plum, walnut, pineapple, and eggplant. Also avoid tobacco, tea and coffee three days prior to specimen collection. Serotonin levels may be affected by certain types of medications such as morphine, MAO inhibitors, methyldopa, and lithium. It is advisable for a person to check with their prescribing physician to determine if they are taking any medication which may influence their test results.


Specimen Collected
  • Blood
Estimated Time Taken

Turnaround for this test is typically 4-11 business days.