Peripheral Blood CD19+ B-Cells and CD20 Expression
Normal reference intervals for circulating B-lineage cells measured by flow cytometry vary by laboratory, reagent, gating strategy, and patient age. Published institutional reference ranges are commonly reported as both the percentage of lymphocytes and the absolute count per µL (cells/mcL). [1], [2], [3]
CD19+ B-Cells Reference Ranges (Adult)
- CD19+ B cells, % of lymphocytes (adult): 6%–25%. [1]
- CD19+ B cells, absolute count (adult): 86–488 cells/µL. [1]
- CD19+ B cells, % of lymphocytes (adult, alternative interval): 4.6%–22.1%. [2]
- CD19+ B cells, absolute count (adult, alternative interval): 56.6–417.4 cells/µL. [2]
CD20 Expression on B-Cells Reference Ranges (Adult)
- CD20+ B cells, % of lymphocytes (adult): 5.0%–22.3%. [2]
- CD20+ B cells, absolute count (adult): 74.4–441.1 cells/µL. [2]
- CD20+ B cells, % of lymphocytes (age >18 years, alternative interval): 6%–12%. [3]
- CD20+ B cells, absolute count (age >18 years, alternative interval): 14–346 cells/cmm. [3]
Age-Related Variation in Reference Intervals
- Pediatric reference intervals for CD19+ B cells show age-dependent changes in both percent and absolute counts. [1]
- Pediatric reference intervals for CD19+ B cells and CD20+ B cells are also age-dependent in published laboratory reference documents. [3]
Common Pitfalls to Avoid
- Results should not be interpreted without the laboratory’s reference interval, because gating strategy and reagent performance affect both CD19 and CD20 percentages and absolute counts. [1], [2], [3]
- Anti-CD20 monoclonal antibody therapy can interfere with CD20 detection, resulting in decreased measured CD20 expression despite the presence of B cells. [2]
Interpretation of “CD20 Expression” in Practice
- CD20 is typically reported as CD20+ B-cell frequency (percentage of lymphocytes) and CD20+ absolute count by flow cytometry rather than as a single universal continuous “expression level.” [2], [3]