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HelpTest ID CD20B CD20 on B Cells, Blood
Useful For
Evaluation of patients with a suspected CD19 deficiency (humoral immunodeficiency)
Confirming complete absence of B cells in suspected primary humoral immunodeficiencies using both CD19 and CD20 markers
Assessing therapeutic B-cell depletion quantitatively (absolute counts of cells/mcL) in any clinical context, including malignancies, autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and membranous glomerulonephritis among others, and treatment or prevention of acute humoral rejection in positive crossmatch renal transplant recipients
This test is not useful for assessing whether B cells express the target molecule (CD20) in the context of initiating therapeutic monoclonal anti-CD20 antibody therapy (rituximab, ofatumumab, and tositumomab) for any of the hematological malignancies, or in other clinical contexts, such as autoimmunity.
Method Name
Flow Cytometry
Reporting Name
CD20, B-CellsSpecimen Type
Whole Blood EDTAOrdering Guidance
This is the correct test to order if specifically confirming the absence of B cells due to suspected primary humoral or combined immunodeficiency or evaluating for CD19 deficiency.
If desirous of only quantitatively measuring total CD19 or CD20+ B cells, order TBBS / Quantitative Lymphocyte Subsets: T, B, and Natural Killer (NK) Cells, Blood or CD20B / CD20 on B Cells, Blood, respectively. Do not order the detailed analysis of B cell subsets for this purpose.
This test should not be ordered for a comprehensive evaluation of peripheral B-cell subsets. For evaluation of memory B-cell subsets, transitional B cells, mature and immature B cells, order IABCS / B-Cell Phenotyping Profile for Immunodeficiency and Immune Competence Assessment, Blood.
This test should not be used for evaluating presence of CD20 on malignant or nonmalignant B cells. The following test should be ordered instead, CEE20 / CD20 Cell Expression Evaluation, Varies.
Shipping Instructions
Collect and package specimens as close to shipping time as possible.
It is recommended that specimens arrive within 24 hours of collection.
Necessary Information
Date and time of collection is required.
Specimen Required
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.
Additional Information:
1. Secondary aliquot tubes will be rejected.
2. Testing will be canceled if the specimen is not received ambient.
3. For serial monitoring, it is recommended that specimens are collected at the same time of day.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole Blood EDTA | Ambient | 4 days | PURPLE OR PINK TOP/EDTA |
Reference Values
%CD19 B Cells
≥19 years: 4.6-22.1%
CD19 Absolute
≥19 years: 56.6-417.4 cells/mcL
%CD20 B Cells
≥19 years: 5.0-22.3%
CD20 Absolute
≥19 years: 74.4-441.1 cells/mcL
CD45 Absolute
18-55 years: 0.99-3.15 thou/mcL
>55 years: 1.00-3.33 thou/mcL
Day(s) Performed
Monday through Sunday
Resulted Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
86355
86356
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CD20B | CD20, B-Cells | 100994-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 89584 | CD45 Absolute | 27071-0 |
| 29579 | %CD19 B-Cells | 8117-4 |
| 29580 | %CD20 B-Cells | 8119-0 |
| 29581 | CD19 Absolute | 8116-6 |
| 29582 | CD20 Absolute | 9558-8 |
| 29583 | Comment | 48767-8 |