Serotonin Release Test (24-Hour Urine)
This test measures serotonin, a chemical produced by the body that helps regulate mood, sleep, and appetite. It’s often used to check for conditions like serotonin syndrome or to monitor serotonin levels in urine over a full day.
["Assesses serotonin excretion in urine to help diagnose or monitor certain neurological or psychiatric conditions."]
Key facts at a glance
- LOINC
- 68501-6
- Short code
- Serotonin release.UHF+LMW pnl Ser
- Synonyms
- Serotonin release.UHF+LMW pnl Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test if you have symptoms like confusion, rapid heartbeat, or muscle spasms that could suggest serotonin syndrome—a potentially serious condition caused by too much serotonin in the body. It may also be used to evaluate serotonin metabolism in conditions like serotonin syndrome, carcinoid syndrome, or certain genetic disorders.
What to Expect Before the Test
You’ll need to collect all urine for a full 24-hour period in a special container. Drink plenty of fluids to ensure full collection. Avoid medications that may affect serotonin levels unless approved by your provider.
What Happens During the Test
After collecting urine, it’s sent to a lab for analysis. The test measures serotonin concentration in your urine over the day. No special preparation beyond urine collection is typically required.
Possible Results and Their Meaning
Higher-than-normal serotonin levels may indicate conditions like serotonin syndrome or carcinoid syndrome. Lower-than-normal levels might suggest genetic disorders affecting serotonin production. Your doctor will interpret results in the context of your symptoms and medical history.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Serotonin Release Test
Short name
Serotonin Urine Test (24h)
Frequently asked questions
What does my serotonin level mean?
How often should I get this test?
Can I take medications before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy