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Serotonin Blood Test

* This is not a home test kit. You will need to visit a local lab for testing.

Serotonin Blood Test

Also Known As

Serotonin Serum Test, 5-Hydroxytryptamine Test, 5-HT Blood Test

Purpose of the Serotonin Blood Test

A serotonin lab test is required to diagnose carcinoid tumors, rare cancerous tumors that cause overproduction of serotonin. Doctors may also request a test for serotonin levels to verify depression and anxiety disorders.

Serotonin Serum (29851)
Serotonin Serum (120204)

What Does the Serotonin Level Test Measure?

Serotonin testing evaluates the amount of serotonin, a neurotransmitter produced by neurons in the brainstem and intestinal cells.

As the gastrointestinal tract makes 95% of serotonin, the Serotonin lab test also helps diagnose carcinoid syndrome caused by a malignant tumor growing in the stomach, colon, small intestine, rectum, and appendix. The condition results in too much serotonin production.

Who Should Take a Blood Test for Serotonin?

Those who show symptoms of abnormal serotonin levels should take the Serotonin lab test. Likewise, individuals evaluated for depression, obsessive-compulsive disorder (OCD), and other mental illnesses are advised to take the serotonin blood test.

Low Serotonin Levels Symptoms

  • Hyperactivity
  • Incontinence
  • Mood swings
  • Chronic fatigue
  • Premature ejaculation
  • Trouble concentrating
  • Changes in the sleep pattern
  • Problems in balance and coordination
  • Extreme sadness and hopelessness (depression)

High Serotonin Levels Symptoms

  • Tremor
  • Diarrhea
  • Seizures
  • Insomnia
  • High fever
  • Confusion
  • Restlessness
  • Hallucinations
  • Unconsciousness
  • Increased heart rate
  • High blood pressure
  • Nausea and vomiting
  • Increased reflexes and muscle twitching

Serotonin Lab Test Preparation

Taking drugs containing the antidepressant monoamine oxidase inhibitors (MAOIs) should be stopped for at least one week before the blood collection. Other than this instruction, no other special preparation is required.

Serotonin Test Results

The standard measurement for serotonin levels depends on the lab procedure, including the volume of the specimen drawn. Hence, it’s essential to focus and compare your results to the reference interval indicated on the test result.

The following are normal serotonin level ranges set by Personalab’s affiliate medical laboratories:

  • Labcorp Serotonin Normal Reference Range: 31 to 207 ng/mL
  • Quest Diagnostics Normal Reference Range: 56 to 244 ng/mL

Results below the reference interval for normal serotonin levels indicate serotonin deficiency which comes with psychological problems like depression, social anxiety disorder, and post-traumatic stress disorder (PTSD).

On the other hand, high serotonin doesn’t entail good health either. In fact, it can be a potentially life-threatening situation if you have elevated serotonin – also known as serotonin syndrome. Excessive serotonin can also be released due to carcinoid syndrome (intestinal tumor).

Where Can I Get Serotonin Testing Done Near Me?

The easiest way to take a serotonin blood test is by ordering it online. Here are the steps to take in doing so.

Step 1: Check out our website’s Hormone Testing section. Then, order the serotonin blood test online and download the order for the lab test, which serves as your doctor’s order.

Step 2: Find a partner medical laboratory near you using our lab locator.

Step 3: Go to the lab of your choice and have your blood sample drawn.

Step 4: Wait for the lab test results within 2-10 business days in your Personalabs account.

For an exact turnaround time for results, please contact us at 1-888-438-5227. We will contact the lab you chose (Quest Diagnostics or Labcorp) as turnaround times vary depending on testing location or lab testing provider.

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Order Your Test

Create an account, choose your tests, checkout securely, generate your lab order



Generate & Print Out Lab Order

Our physician network will approve your order within 2-4hrs.



Visit the Lab

The test price decides which lab you will visit: Quest or Labcorp. Find a location in your area.



Get Your Results

Results can be provided in as little as 24-48 hrs. For more complex tests, please contact us for turn around times.


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