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Serum/Plasma Soluble Interleukin-6 (sIL-6) Concentration

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

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

Quick summary

["Soluble 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
108732-9
Short code
Sol Il2 Recep Msmt SerPl
Synonyms
Sol Il2 Recep Msmt SerPl
Category
coagulation
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 Is This Test Done?

Your healthcare provider may order this test to evaluate inflammation, immune system function, or to monitor conditions such as rheumatoid arthritis, lupus, or certain cancers. It can also help assess responses to treatments for inflammatory diseases.

What Does the Result Mean?

Higher than expected levels may suggest an active inflammatory process, infection, or other immune-related conditions. Lower levels might indicate reduced inflammation or immune activity, though this depends on clinical context. Results are interpreted with your overall health and symptoms in mind.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma, where the soluble IL-6 protein is measured using a sensitive immunoassay method.

What Should You Do Before the Test?

Avoid strenuous exercise or significant physical activity 24 hours before the test, as it may affect inflammation markers like IL-6. If you’re on medications that influence inflammation (e.g., steroids), discuss this with your provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IL-6 (soluble)

Frequently asked questions

What conditions might affect this test?
Conditions such as infections, autoimmune diseases (e.g., rheumatoid arthritis, lupus), inflammatory bowel disease, or certain cancers can raise soluble IL-6 levels. Chronic stress, obesity, or pregnancy may also influence results. Recent infections, trauma, or surgery can temporarily spike IL-6.
Can diet or supplements impact this test?
Dietary factors like high-fat or high-sugar meals may briefly elevate inflammation markers, including IL-6, but results are typically interpreted in the context of your overall health. Avoiding heavy meals 24 hours before testing helps minimize variability. Some supplements (e.g., omega-3s) may have mild anti-inflammatory effects.
How often is this test repeated?
Your provider will determine how often to repeat this test based on your condition and response to treatment. For chronic conditions, tests may be done periodically to monitor progression or treatment effectiveness. Follow-up schedules are personalized.
  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