Interleukin-8 Blood Test: Meaning, Levels, and Interpretation

Interleukin-8 (IL-8) is a pro-inflammatory cytokine measured in a blood test to assess active inflammation. Normal Interleukin 8 levels are typically 0–62 pg/mL in adults. High IL-8 indicates infection, tissue damage, or chronic inflammation, while low levels are usually normal or reflect suppressed immune activity. This marker helps evaluate immune response and inflammatory conditions.

Contents

Result interpretation Interleukin-8

What your result means based on common reference ranges

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Normal

Interleukin-8 levels within 0–62 pg/mL reflect baseline immune activity without significant inflammation or infection.

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Mildly elevated

Mildly elevated IL-8 levels suggest low-grade inflammation or localized infection, often seen in early immune response stages.

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Significantly elevated

High IL-8 levels above 150 pg/mL indicate systemic inflammation, severe infection, or cytokine-mediated tissue damage such as sepsis.

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Below normal

Low Interleukin-8 levels are typically normal but may reflect suppressed immune response due to immunosuppressive therapy.

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What is Interleukin-8?

Interleukin-8 is a chemokine involved in the immune system's response to infection and injury. Its main function is to recruit neutrophils to sites of inflammation, making it a key marker of neutrophilic inflammation. In a blood test, elevated IL-8 levels are associated with bacterial infections, sepsis, and chronic inflammatory diseases such as rheumatoid arthritis. Unlike general markers like CRP, IL-8 provides insight into specific immune pathways. Monitoring IL-8 levels helps assess inflammation severity, treatment response, and immune activation patterns in clinical practice.

Reference ranges

Group Normal range Unit
Adult Men 0 – 62 pg/mL
Adult Women 0 – 62 pg/mL
Children 0 – 50 pg/mL

Causes of abnormal values

Causes of low Interleukin-8

  • • Immunosuppressive therapy: reduces cytokine production and immune signaling
  • • Chemotherapy: damages immune cells responsible for cytokine synthesis
  • • Severe malnutrition: protein deficiency limits immune molecule production

Causes of high Interleukin-8

  • • Bacterial infections: stimulate IL-8 release to recruit neutrophils for pathogen elimination
  • • Rheumatoid arthritis: chronic joint inflammation drives continuous cytokine production
  • • Sepsis: systemic immune activation causes excessive IL-8 and cytokine storm
  • • Smoking: lung irritation induces persistent inflammatory signaling
  • • Acute pancreatitis: tissue damage triggers strong inflammatory mediator release
  • • Psoriasis: immune dysregulation leads to elevated cytokine-driven skin inflammation

Interleukin-8 in combination with other markers

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High IL-8 + High CRP Indicates active systemic inflammation with strong immune activation and acute phase response involvement
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High IL-8 + High Neutrophils Suggests acute bacterial infection with coordinated chemokine signaling and cellular immune response
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High IL-8 + High Procalcitonin Strong indicator of bacterial sepsis with high risk of systemic inflammatory response syndrome
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Low IL-8 + Low White Blood Cells Reflects immune suppression or bone marrow dysfunction reducing both signaling and cellular defense

Possible symptoms

  • •Persistent fever
  • •Local redness and swelling
  • •Fatigue and weakness
  • •Joint pain and stiffness
  • •Shortness of breath

When to see a doctor

Consult a doctor if Interleukin-8 levels exceed 150 pg/mL or continue rising over time. Seek medical attention if elevated IL-8 is accompanied by fever, joint swelling, or weakness. Urgent evaluation is needed if symptoms suggest systemic infection or sepsis.

What to do if abnormal

  • 🧪 Identify cause with additional tests and clinical evaluation
  • 🚭 Reduce inflammation triggers such as smoking
  • 🥗 Improve nutrition to support immune balance
  • 📊 Monitor IL-8 trends with follow-up blood tests
  • 💊 Follow prescribed treatment for underlying conditions

The information on this page is intended for general understanding of test results and does not replace medical consultation. Accurate interpretation requires considering other blood markers and individual factors.

Content is based on medical literature and used within the PulseBook analytical system.

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Frequently asked questions

What is Interleukin 8 and what is its function?

Interleukin-8 is a pro-inflammatory cytokine that acts as a signaling molecule in the immune system. Its main function is to attract neutrophils to sites of infection or tissue damage. In a blood test, IL-8 reflects how actively the body is responding to inflammation, especially in bacterial infections and acute immune responses.

What is the normal range for Interleukin 8?

The normal Interleukin 8 range in adults is typically 0–62 pg/mL, while children may have slightly lower upper limits. Values can vary slightly between laboratories. Low levels are expected in healthy individuals, as IL-8 is produced mainly during active immune responses rather than at baseline.

What does high IL-8 mean?

High IL-8 levels indicate active inflammation in the body. This may be due to bacterial infections, autoimmune diseases, or tissue injury. In severe cases, such as sepsis, IL-8 rises significantly as part of a cytokine storm. It is not specific to one disease but signals an ongoing inflammatory process.

Is IL-8 pro or anti inflammatory?

IL-8 is strictly pro-inflammatory. It plays a central role in initiating and maintaining inflammation by recruiting neutrophils. While this is essential for fighting infections, excessive IL-8 activity can contribute to chronic inflammation and tissue damage.

What does IL8 neutrophil interaction mean?

IL-8 directly signals neutrophils to migrate to areas of infection or injury. This interaction is critical for the immune response, as neutrophils are among the first cells to attack pathogens. High IL-8 with high neutrophils typically indicates bacterial infection or acute inflammation.

Can stress increase Interleukin-8 levels?

Chronic stress can contribute to systemic inflammation and may elevate IL-8 levels over time. While stress alone is usually not the primary cause of high IL-8, it can amplify inflammatory responses and worsen underlying conditions.

Is Interleukin-8 used as a cancer marker?

Interleukin-8 can be elevated in some cancers, as tumors may produce inflammatory cytokines. However, it is not used as a standalone cancer diagnostic marker. Elevated IL-8 is more commonly linked to infections or inflammatory diseases than malignancy.