Complement C2 Antigen (C2)
Single-chain glycoprotein cleaved by activated C1s or MASP-2 into C2a and C2b during classical and lectin complement activation.
Standard vs. Optimal Reference Rangesug/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.
Your value falls within the optimal target associated with lowest disease risk and longevity.
15 - 35 ug/mL (1.5 - 3.5 mg/dL)
General reference distribution across unselected commercial populations.
18 - 30 ug/mL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
C2a associates with C4b on target membranes to form the classic C3 convertase (C4b2a), cleaving C3 into C3a and C3b.
Differential Diagnosis
Elevated Levels (C2 High)
- •Acute phase reactant elevation
Low Levels (C2 Low)
- •Inherited C2 deficiency (homozygous, predisposing to SLE, discoid lupus, and Streptococcus pneumoniae bacteremia)
- •Active immune complex consumption
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Specimen collection should follow standardized phlebotomy protocols. Protect from hemolysis, centrifuge promptly, and freeze serum or plasma if testing is delayed. Patient should be in a resting, fasting state where indicated.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker quantification for C2
- Targeted organ system imaging or functional dynamic testing related to c3/c5 convertase component
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of Complement C2 Antigen - The New England Journal of Medicine (2021). PMID: 34190124
- [2]C2 Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35422901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Complement C2 Antigen (C2) into overall healthspan optimization.