B-Cell CD20 Expression
Also known as: % CD20 B Lymphocytes, CD20, CD20 on B Lymphocytes
Use
This test can be used in assessing therapeutic B-cell depletion in any clinical context, including Multiple Sclerosis, 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. It can be used in the evaluation of CD20 deficiency in patients with suspected CD19 deficiency (humoral immunodeficiency), and it can be used to confirm the complete absence of B cells in suspected primary humoral immunodeficiencies using both CD19 and CD20 markers.
Special Instructions
Collect specimens Monday through Wednesday only. Indicate date and time of venipuncture on the tube(s) and on the test request form. This assay is not available in New York state.
Limitations
Timing and consistency in the timing of blood collection are critical for monitoring patients for lymphocyte subsets. The test performance characteristics have been determined by Labcorp and it is performed in a CLIA certified laboratory for clinical purposes. However, it is not cleared or approved by the FDA. Monoclonal antibody-based therapies may block available CD20-binding sites, which can affect recognition by the assay. The concurrent use of CD19 markers provides additional insights on B-cell depletion with this assay.
Methodology
Cell-based / Cytometry (Flow Cytometry)
Biomarkers
LOINC Codes
- 94689-7
- 8117-4
- 8119-0
Result Turnaround Time
3-4 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Fill tube(s) to capacity
Minimum Volume
0.5 mL
Container
Yellow-top (ACD) tube or lavender-top (EDTA) tube
Collection Instructions
Invert tube 8 to 10 times immediately after collection. To preserve cellular viability, collect specimen so it will arrive in the laboratory within 72 hours of collection. Indicate date and time of venipuncture on the tube(s) and on the test request form.
Storage Instructions
Room temperature
Causes for Rejection
Hemolysis; specimen refrigerated or frozen; clotted specimen; contaminated specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | Unstable |
| Frozen | Unstable |