Interleukin-6 (IL-6) mass concentration in serum/plasma
This test measures the amount of interleukin-6, a protein involved in inflammation and immune response, in your blood.
["IL-6 helps your body respond to infections, injuries, or stress and can indicate inflammation or immune activity."]
Key facts at a glance
- LOINC
- 13629-1
- Short code
- Il1Beta SerPl-mCnc
- Synonyms
- Il1Beta SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 an IL-6 test to evaluate symptoms like fever, fatigue, joint pain, or swelling that suggest inflammation. It can also help diagnose conditions such as autoimmune diseases, infections, or certain cancers, where IL-6 levels may be elevated.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if instructed, but this depends on your provider. Bring any medications you’re currently taking.
How the Test Is Performed
A blood sample is drawn from a vein, typically in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort afterward.
Possible Results and Their Meaning
Results can vary widely based on your health, activity level, and other factors. High IL-6 levels may indicate inflammation, infection, or certain diseases. Low levels might suggest a reduced immune response or other conditions. Your provider will interpret the result in the context of your symptoms and medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IL-6 Level
Frequently asked questions
IL-6 is a key marker for inflammation and immune activity. Elevated levels can signal acute infections, chronic inflammatory diseases (like rheumatoid arthritis), or conditions such as sepsis, where the body’s immune response is overactive. It may also play a role in certain cancers, where it can promote tumor growth.
An elevated IL-6 level often suggests an ongoing inflammatory process or immune response. This could be due to infections, autoimmune diseases, or other conditions that trigger high levels of this protein. Your doctor will discuss the results with you and may recommend further testing or treatments based on the cause.
Yes, lifestyle factors can influence IL-6 levels. High-stress situations, poor sleep, or certain diets (like very high in sugar or processed foods) may temporarily increase inflammation. Regular physical activity, a balanced diet, and stress management can help keep levels more stable.
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