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Interleukin-6 (IL-6)

Published: July 27, 2026Updated: August 25, 2026

IL-6 is a cytokine that plays a crucial role in inflammation and immune response. It is often measured to assess the severity of inflammatory conditions and monitor treatment effectiveness.

Quick summary

IL-6 is a key inflammatory biomarker used to diagnose and monitor inflammatory conditions.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
pg/mL
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Roche IL-6, Abbott IL-6, R&D Systems IL-6 ELISA
interpretation: {"text":"0–5 pg/mL: IL-6 levels within this range are considered normal and indicate a low level of inflammation.","label":"Normal"}; {"text":">5 pg/mL: Levels above the reference range may indicate the presence of an inflammatory condition or infection.","label":"Elevated"}

Interleukin-6 (IL-6) is a multifunctional cytokine involved in a variety of biological processes, including inflammation, immune response, and hematopoiesis. It is produced by various cells, including T-cells, macrophages, and endothelial cells, in response to infections and tissue injuries.

Elevated levels of IL-6 are associated with acute and chronic inflammatory conditions, such as rheumatoid arthritis, systemic juvenile idiopathic arthritis, and cytokine release syndrome. Monitoring IL-6 levels can help in assessing disease activity and guiding treatment strategies.

In clinical settings, IL-6 testing is often used to support the diagnosis of inflammatory disorders and to evaluate the effectiveness of anti-inflammatory therapies. It is also used in the management of patients with severe infections and in assessing the risk of complications in certain medical conditions.

Frequently asked questions

What conditions can cause elevated IL-6 levels?
Elevated IL-6 levels can be caused by inflammatory conditions such as rheumatoid arthritis, systemic juvenile idiopathic arthritis, and cytokine release syndrome, as well as severe infections and certain cancers.
How is an IL-6 test performed?
An IL-6 test is performed using a blood sample. The sample is typically collected through a vein in the arm and sent to a laboratory for analysis.
  1. 1
    Interleukin-6 (IL-6)Source
  2. 2
    IL-6 as a biomarker of inflammationSource

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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 25, 2026. · Read our editorial policy