Skip to content

Interleukin-6 (IL-6) Substance Concentration in Serum or 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 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
108730-3
Short code
Il6 Msmt SerPl
Synonyms
Il6 Msmt SerPl
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 It’s Ordered

Your doctor may order this test to check for inflammation, autoimmune conditions, or reactions to infections, treatments, or injuries. It can also help monitor conditions like rheumatoid arthritis, lupus, or certain cancers.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Higher than normal levels may indicate inflammation, infections, or conditions like cancer or autoimmune diseases. Lower levels might suggest immune system suppression or certain liver issues. Your doctor will interpret results based on your health history.

Common Conditions Monitored

IL-6 levels are often checked in people with autoimmune diseases (e.g., rheumatoid arthritis, lupus), infections, or after chemotherapy to track how well treatments are working.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IL-6 Level

Frequently asked questions

What causes IL-6 levels to be high?
IL-6 levels can rise due to infections (like flu or sepsis), autoimmune diseases (such as rheumatoid arthritis or lupus), injuries, or certain cancers. Stress, pregnancy, or some medications may also affect it.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab. Your doctor will discuss them with you during your follow-up visit.
Can diet or exercise affect IL-6 levels?
Dietary inflammation (e.g., high in sugar or processed foods) or intense exercise can temporarily raise IL-6 levels, but this is usually short-term. Your doctor will consider lifestyle factors when interpreting results.
  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