Time Sensitive

Ordering Recommendation

Used primarily to monitor response to rituximab therapy.

New York DOH Approval Status

This test is New York state approved.

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


Flow Cytometry




1-2 days

Reference Interval

By report

Interpretive Data

Refer to report.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Analyte Specific Reagent (ASR)


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.

Hotline History


CPT Codes

88184; 88185


Component Test Code* Component Chart Name LOINC
0095234 Interpretation 50595-8
* 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.


  • CD19
  • CD20 on B Cells
  • Rituximab Therapy CD20
B-Cell CD20 Expression