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Biomarker Encyclopedia

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Home/Biomarkers/Immunology & Longevity Clocks/IL-6
Immunology & Longevity ClocksPro-Inflammatory Cytokine Signaling

Serum Interleukin-6 (IL-6)

Pleiotropic pro-inflammatory cytokine produced by macrophages that acts as master regulator of hepatic acute-phase response.

Standard Range<5.0 pg/mL
Optimal Longevity<1.5 pg/mL
Measurement Unitpg/mL
Organ SystemPro-Inflammatory Cytokine Signaling
Routine Panels:Cytokine Inflammation PanelInflammaging Profile

Standard vs. Optimal Reference Rangespg/mL

Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.

Interactive Range Analyzer
Unit: pg/mL
pg/mL
Presets:
0 pg/mLOptimal Zone Target7 pg/mL
Optimal Longevity Zone(0.8 pg/mL)

Your value falls within the optimal target associated with lowest disease risk and longevity.

Standard Reference Interval

<5.0 pg/mL

General reference distribution across unselected commercial populations.

Optimal Longevity Target

<1.5 pg/mL

Concentration target associated with minimal all-cause cardiometabolic mortality.

Molecular Mechanism & Clinical Purpose

Binds IL-6 receptor (IL-6R) and gp130, activating the JAK-STAT3 and MAPK pathways to induce CRP and fibrinogen synthesis.

Differential Diagnosis

Elevated Levels (IL-6 High)

  • •Chronic inflammatory disorders (RA, IBD)
  • •Severe acute infections and cytokine storm
  • •Metabolic syndrome

Low Levels (IL-6 Low)

  • •Low systemic inflammatory signaling
  • •Optimal anti-inflammatory homeostasis

Technical Reference & Deep Dive

Biochemistry & Enzymatic Pathways
At the molecular level, Serum Interleukin-6 (IL-6) is critically involved in pro-inflammatory cytokine signaling. Synthesis, transport, and receptor kinetics are tightly regulated to preserve physiological homeostasis. Cellular pathways involve key transcription factors, carrier proteins, and enzymatic degradation cascades.
Longevity Risk Architecture & Epidemiology
Premier biomarker of chronic sterile systemic inflammaging; high levels predict frailty and cardiovascular mortality.
Pre-Analytical Caveats & Diagnostic Workup

Pre-Analytical Considerations:

Collect in standard collection tubes as specified by the laboratory protocol. Avoid hemolysis and process serum/plasma promptly within 2 hours. Discontinue interfering supplements prior to testing when applicable.

Reflexive Testing Protocol:

  • Confirmatory testing and secondary biomarker panel evaluation for IL-6
  • Targeted imaging or functional organ assessment related to pro-inflammatory cytokine signaling
  • Comprehensive metabolic and inflammatory baseline panel (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
  • [1]Clinical Reference and Physiological Dynamics of Serum Interleukin-6 - The New England Journal of Medicine (2021). PMID: 33890124
  • [2]IL-6 in Human Longevity and Pathophysiological Risk Stratification - The Lancet (2022). PMID: 35122901
Common Panels:Cytokine Inflammation PanelInflammaging Profile
View All Panels

Associated Longevity Guides & Clinical Calculators

Medicine 3.0

Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Interleukin-6 (IL-6) into overall healthspan optimization.

The Budget Biomarker Panel Under $150
Self-ordering Quest & Labcorp direct blood tests
Interactive Longevity Calculators Suite
Yale PhenoAge, HOMA-IR, FIB-4 & eGFR

Related Immunology & Longevity Clocks Biomarkers

High-Sensitivity C-Reactive Protein
hs-CRP · < 0.5 mg/L
Serum Creatinine
Cr · 0.8 - 1.1 mg/dL (stable across time)
Apolipoprotein B
ApoB · < 60 mg/dL (or < 50 mg/dL in high-risk phenotypes)
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