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Serum/plasma concentration of interleukin-6 (IL-6)

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

This test measures the amount of interleukin-6, a protein involved in inflammation and immune response, in your blood.

Quick summary

["IL-6 helps your body respond to infections, injuries, or chronic conditions like arthritis or cancer."]

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

Key facts at a glance

LOINC
42899-5
Short code
CMV IgM CSF Ql IF
Synonyms
CMV IgM CSF Ql IF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order an IL-6 test to check for inflammation, diagnose conditions like rheumatoid arthritis, lupus, or certain infections, or monitor treatment responses for diseases affecting your immune system.

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 your lab requires it, but this depends on the lab’s protocol. Bring any medications you’re taking.

How the Test Is Done

A blood sample is drawn from a vein in your arm by a healthcare professional. You may feel a slight pinch, but it usually doesn’t cause discomfort afterward.

What the Results Mean

Higher-than-normal IL-6 levels may suggest inflammation, infection, or autoimmune conditions. Lower-than-normal levels might indicate a suppressed immune response, though this is less common. Your results will be interpreted by your provider 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

What causes elevated IL-6 levels?
Elevated IL-6 can result from infections (e.g., bacterial or viral), autoimmune diseases (e.g., rheumatoid arthritis, lupus), inflammatory conditions, trauma, or certain cancers. Your provider will consider your symptoms and medical history to determine the cause.
How long does it take to get IL-6 test results?
Results are typically available within 1–3 business days, depending on the lab. Your provider will contact you once they’re ready to discuss the findings.
Can lifestyle changes affect IL-6 levels?
Yes, factors like stress, poor sleep, obesity, or certain medications (e.g., steroids) may influence IL-6 levels. If you suspect lifestyle changes are affecting your test results, discuss this with your provider before or after your 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