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Interleukin-6 (IL-6) concentration in serum/plasma

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

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

Quick summary

["IL-6 helps your immune system fight off illness and signals your body to produce more immune cells."]

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

Key facts at a glance

LOINC
44599-9
Short code
M-IgG CSF Ql IFE
Synonyms
M-IgG CSF Ql IFE
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immunofixation
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
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, or swelling that could indicate an inflammatory condition, infection, or autoimmune disease. It may also be used to monitor treatment responses in certain conditions, such as rheumatoid arthritis or sepsis.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before your blood is drawn. Wear a loose shirt for easy access to your arm.

How the Test Is Performed

A healthcare professional will insert a needle into a vein in your arm to collect a blood sample. You may feel a small pinch, but the procedure is quick and typically painless.

What the Results Mean

Elevated IL-6 levels may suggest an active inflammatory process, infection, or other conditions affecting immune response. Lower than expected levels might indicate suppressed immune function or certain genetic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IL-6 Level

Frequently asked questions

What are common reasons for abnormal IL-6 levels?
Abnormally high IL-6 levels can be linked to conditions like rheumatoid arthritis, sepsis, or inflammatory bowel disease. Very low levels may be seen in rare genetic disorders or during certain medications that suppress immune activity.
How long does it take to get results?
Results are usually available within 1 to 3 business days, depending on your lab’s processing schedule.
Can I eat or drink before this test?
Typically, no fasting is required, but always follow your healthcare provider’s instructions for specific test-related guidelines.
  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