Absolute CD19+ B Lymphocytes (B-Cell Count)
Absolute count of peripheral lymphocytes expressing CD19, a transmembrane signaling glycoprotein present across all stages of B-cell development.
Standard vs. Optimal Reference Rangescells/uL
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.
100 - 500 cells/uL (5 - 20% of total lymphocytes)
General reference distribution across unselected commercial populations.
150 - 400 cells/uL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Forms a multi-protein signal transduction complex with CD21 and CD81 on B-cells, lowering the threshold for B-cell receptor (BCR) activation.
Differential Diagnosis
Elevated Levels (B-Cell Count High)
- •B-cell chronic lymphocytic leukemia (CLL)
- •B-cell non-Hodgkin lymphomas
- •Polyclonal B-cell activation
Low Levels (B-Cell Count Low)
- •Common Variable Immunodeficiency (CVID)
- •X-linked Agammaglobulinemia (Bruton disease, absent B-cells)
- •Complete Rituximab anti-CD20 therapeutic depletion (<5 cells/uL)
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 B-Cell Count
- Targeted organ system imaging or functional dynamic testing related to humoral b-cell reserve
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of Absolute CD19+ B Lymphocytes - The New England Journal of Medicine (2021). PMID: 34190124
- [2]B-Cell Count 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 Absolute CD19+ B Lymphocytes (B-Cell Count) into overall healthspan optimization.