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Interleukin-6 (IL-6) Serum Concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of interleukin-6, a protein produced by your body in response to inflammation, infection, or trauma.

Quick summary

["IL-6 helps your immune system fight illness and signals your body to produce other immune factors."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
4652-4
Short code
Il3 SerPl-aCnc
Synonyms
Il3 SerPl-aCnc
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 doctor may recommend this test to check for inflammation, monitor conditions like rheumatoid arthritis, lupus, or cancer, or evaluate responses to treatments that target inflammation or immune responses.

Common Conditions Monitored

High levels of IL-6 are often linked to chronic inflammatory diseases, infections, or certain cancers. Low levels may suggest suppressed immune activity or certain autoimmune conditions.

Sample Collection and Preparation

A blood sample is drawn from a vein in your arm. The blood is processed to separate serum (the liquid part without clotting factors), which is then tested for IL-6 levels.

What to Expect Before the Test

No special preparation is usually needed, but inform your doctor about any medications, especially steroids or immune-modulating drugs, that could affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated IL-6 levels can indicate acute or chronic inflammation, autoimmune diseases, or conditions like sepsis, where the immune system overreacts. It’s also used in research for cancer biomarkers, though not routinely for diagnosis.

Short name

IL-6 Level

Frequently asked questions

What does a high IL-6 level mean?
A high IL-6 level may suggest an active inflammatory process, infection, or certain autoimmune disorders. Your doctor will consider your overall health and symptoms to interpret results.
What does a low IL-6 level mean?
Low IL-6 levels might indicate reduced inflammation or immune activity, but they can also occur in certain genetic or immune-suppressed states. Results should be reviewed with your healthcare provider.
Can IL-6 levels change with diet or exercise?
IL-6 is primarily influenced by immune responses and inflammation. While diet and exercise can indirectly affect inflammation, they do not directly alter IL-6 levels in this test.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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