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HelpTest Code RBCS Relative B-Cell Subset Analysis Percentage, Blood
Reporting Name
Relative B Cell Subset Analysis %Performing Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
Screening for humoral or combined immunodeficiencies, including common variable immunodeficiency, hyper IgM syndrome, among others, where B-cell subset distribution information is desired
Assessing B-cell subset reconstitution after hematopoietic cell or bone marrow transplant
Assessing B-cell subset reconstitution following recovery of B cells after B-cell-depleting immunotherapy
This test is not indicated for the evaluation of lymphoproliferative disorders (eg, leukemia, lymphoma, multiple myeloma).
This test should not be used to monitor B-cell counts to assess B-cell depletion in patients on B-cell-depleting therapies.
Method Name
Flow Cytometry
Ordering Guidance
This test should be ordered only when percentages are needed for the reportable B-cell subsets. If both percentages and absolute counts are needed for the reportable B-cell subsets, order IABCS / B-Cell Phenotyping Profile for Immunodeficiency and Immune Competence Assessment, Blood.
Shipping Instructions
Testing performed Monday through-Friday. Specimens not received by 4 p.m. Central time on Fridays may be canceled.
Specimens arriving on the weekend and observed holidays may be canceled.
Collect and package specimens as close to shipping time as possible. Ship specimens overnight.
It is recommended that specimens arrive within 24 hours of collection.
Necessary Information
The ordering healthcare professional's name and phone number are required.
Specimen Required
Container/Tube: Lavender top (EDTA)
Specimen Volume:
≤14 years: 4 mL
>14 years: 10 mL
Collection Instructions:
1. Send whole blood specimen in original tube. Do not aliquot.
2. Label specimen as blood for RBCS.
Additional Information: For serial monitoring, it is recommended that specimens are collected at the same time of day.
Specimen Type
Whole Blood EDTASpecimen Minimum Volume
≤14 years: 3 mL; >14 years: 5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Refrigerated | 48 hours | PURPLE OR PINK TOP/EDTA |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
Reference Values
The appropriate age-related reference values will be provided on the report.
Interpretation
The assay provides semiquantitative information on the various B-cell subsets. Each specimen is evaluated for B-cell subsets with respect to the total number of CD19+ B cells present in the peripheral blood mononuclear cell population, compared to the reference range. In order to verify that there are no CD19-related defects, CD20 is used as an additional pan-B-cell marker (expressed as percentage of CD45+ lymphocytes).
The B-cell panel assesses the following B-cell subsets:
CD19+=B cells expressing CD19 as a percent of total lymphocytes
CD19+ CD27+=total memory B cells
CD19+ CD27+ IgD+ IgM+=marginal zone or non-switched memory B cells
CD19+ CD27+ IgD- IgM+=IgM-only memory B cells
CD19+ CD27+ IgD- IgM-=class-switched memory B cells
CD19+ IgM+=IgM B cells
CD19+ CD38+ IgM+=transitional B cells
CD19+ CD38+ IgM-=plasmablasts
CD19+ CD21-=CD21-negative B cells
CD19+ CD21+=CD21-positive B cells
CD19+ CD20+=B cells coexpressing both CD19 and CD20 as a percent of total lymphocytes
Day(s) Performed
Monday through Friday
Report Available
3 to 4 daysTest Classification
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
86356 x7
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| RBCS | Relative B Cell Subset Analysis % | 90416-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| BCD19 | CD19+ % of total Lymphocytes | 8117-4 |
| BCD20 | CD20+ % of total Lymphocytes | 8119-0 |
| BCD27 | CD27+ % of CD19+ B Cells | 89358-6 |
| B27MD | CD27+ IgM+ IgD+ % of CD19+ B Cells | 89352-9 |
| B27N | CD27+ IgM- IgD- % of CD19+ B Cells | 89350-3 |
| B27M | CD27+ IgM+ IgD- % of CD19+ B Cells | 89348-7 |
| BIGM | IgM+ % of CD19+ B Cells | 89346-1 |
| B38MN | CD38+ IgM- % of CD19+ B Cells | 89344-6 |
| B38MP | CD38+ IgM+ % of CD19+ B Cells | 89341-2 |
| B21P | CD21+ % of CD19+ B Cells | 89356-0 |
| B21N | CD21- % of CD19+ B Cells | 89355-2 |
| RBCSI | Interpretation | 69048-7 |