Serum or Plasma Free Tryptophan Concentration (Mass Concentration)
This test measures the amount of the amino acid tryptophan in your blood, which can help assess certain metabolic or nutritional conditions.
["Tryptophan levels may be checked if you have symptoms of metabolic disorders or nutritional deficiencies."]
Key facts at a glance
- LOINC
- 110860-4
- Short code
- F tular IgM Msmt Ser
- Synonyms
- F tular IgM Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- 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 Might Be Ordered
Your healthcare provider may order this test if you have symptoms like fatigue, weakness, or changes in mood that could be linked to low tryptophan levels. It may also be used in research or specialized clinical settings to evaluate metabolic pathways or nutritional status.
What to Expect Before the Test
No special preparation is typically needed. You may be asked to fast for a few hours before the blood draw, but this depends on your healthcare provider’s instructions. Bring any medications you’re currently taking.
What the Test Involves
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause significant discomfort. The blood sample will be sent to a lab for analysis.
What the Results Mean
Results are interpreted by your healthcare provider based on your medical history and symptoms. Abnormal levels may indicate conditions like malnutrition, certain metabolic disorders, or other health concerns that require further evaluation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Tryptophan is an essential amino acid involved in the production of serotonin and niacin. Low levels may suggest underlying nutritional deficiencies, metabolic disorders, or conditions affecting amino acid metabolism. High levels could be associated with certain genetic or liver-related conditions and should be discussed with your doctor.
Short name
Free Tryptophan Level
Frequently asked questions
How long does it take to get my results?
What does a low or high tryptophan level indicate?
Check with your healthcare provider for specific instructions, but generally, you may eat a light meal if needed. Some labs may recommend fasting for a few hours before the blood draw.
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