Memory B Cells
Test Code
MEMB
Description
MEMB measures naive, unswitched and switched memory B lymphocytes using direct immunofluorescence staining with specific monoclonal antibodies followed by analysis by flow cytometry. The test is useful for the assessment of B cell subsets in immunodeficiency.
Common variable immunodeficiency (CVID) comprises a clinically heterogeneous group of primary antibody immunodeficiency states. CVID patients are characterized by low levels of immunoglobulins (lgs), especially lgG and lgA, and by B lymphocyte percentages ranging from very low to normal. Populations of CD27+ memory B cells and increased percentages of undifferentiated (or unswitched) B cells may be observed in peripheral blood of patients with CVID.
Collect
Draw one green top tube (Sodium or Lithium Heparin) top tube.
Patient Prep
Preferred volume: 3 mL blood
Pediatric Collection
Minimum volume: 1 mL blood
Unacceptable Conditions
Frozen, clotted, hemolyzed or centrifuged specimens. Anticoagulants other than heparin. Specimens >24 hrs old.
Storage Transport Temp
Maintain and transport specimens at room temperature (18-22°C).
Ship specimens Priority Overnight via Fed Ex in container sufficiently insulated to avoid temperature extremes (<10°C and >37°C).
Stability
24 hours at room temperature (18-22°C)
Notes
Samples must be received within 24 hours of draw. Samples are accepted Monday through noon on Friday.
Performed
Tuesday - Friday
Methodology
Flow Cytometry
Turnaround Time
4 days
Department
Immunology Lab - Phenotyping Assays
Synonyms
B cell subsets, Flow Cytometry (Memory B Cells), MEMB, CD27 IgD B cell surface immunoglobulin, immunodeficiency, switched B cells
Study Offerings
RUO
CAP/CLIA
Related Tests
Reference Interval
| % of CD20 B cells | 1 Year | 2-3 Years | 4-5 Years | 6-10 Years | 11-18 Years | >18 Years |
| CD27+/IgD+ (unswitched) | 3.3 - 10.8 | 4.9 - 14.2 | 7 - 15.2 | 2.9 - 19 | 5.0 - 17.9 | 3.8 - 52.7 |
| CD27+/IgD- (switched) | 1.0 - 5.0 | 2.9 - 9.2 | 3.9 - 16.2 | 3.8 - 16.5 | 4.0 - 22.8 | 1.9 - 30.4 |
| CD27-/IgD+ (naive) | 83.3 - 93.7 | 74.7 - 90.5 | 70.7 - 85 | 63.1 - 89.2 | 60.2 - 88.9 | 24.4 - 90.6 |
Huck, K., et al., Memory B-cells in healthy and antibody-deficient children. Clin Immunol. 2009. 131(1): p. 50-59.
Interpretation
Analysis of switched and unswitched memory B cells is useful for the assessment of B cell subsets in immunodeficiency.
CPT Code
88184, 88185 x2
New York Approved
No: Run with Waiver
FDA
LDT