B-Cell CD20 Expression
Ordering Recommendation

Used primarily to monitor response to rituximab therapy.

Flow Cytometry
1-2 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Flow Cytometry Test Request Form RecommendedFlow Cytometry Test Request Form Recommended
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Green (sodium heparin). Also acceptable: Lavender (EDTA) or pink (K2EDTA).  
Specimen Preparation
Transport 5 mL whole blood.  
Storage/Transport Temperature
Room temperature. Also acceptable: Refrigerated. Specimen should be received within 48 hours of collection for optimal viable testing.  
Unacceptable Conditions
Frozen specimens. Specimens greater than 48 hours old. Clotted or hemolyzed specimens.  
Provide CBC, Wright's stained smear (if available), clinical history, differential diagnosis, and any relevant pathology reports.  
Ambient: 48 hours; Refrigerated: 48 hours; Frozen: Unacceptable  
Reference Interval
By report
Interpretive Data
Refer to report.

Compliance Statement A: For laboratory developed tests using a manufacturer labeled ASR as the reagent providing the specificity of the assay. Analyte Specific Reagent. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, the FDA has determined that such clearance or approval is not necessary.
Monoclonal antibody-based therapies such as Rituximab that target the CD20 antigen, are being used to treat patients with a variety of B-cell lymphomas and leukemias, as well as in the treatment of some autoimmune disorders. The effectiveness of these therapies for B-cell lymphomas and leukemias requires that the B-cell leukemia or lymphoma cells express CD20. This test examines whether surface CD20 antigen expression can be identified on any B-cells present in the submitted specimen. This test will also identify CD19 antigen expression and the percentage of expression.
CPT Code(s)
88184; 88185; 88187
Component Test Code*Component Chart NameLOINC
0096213% CD198117-4
0096214% CD208119-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • CD20 on B Cells
  • Rituximab Therapy CD20