CD20B - Specimen: CD20 on B Cells

Test Catalog

Test Name

Test ID: CD20B    
CD20 on B Cells

Specimen Type Describes the specimen type validated for testing

Whole Blood EDTA

Advisory Information

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 / T- and B-Cell Quantitation by Flow Cytometry or CD20B / CD20 on B Cells, 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 used instead, TAE / Therapeutic Antibody by Flow Cytometry, which provides percent of B cells expressing CD19 or CD20 but does not provide absolute cell counts (cells/mcL).

Shipping Instructions

Draw and package specimens as close to shipping time as possible. It is recommended that specimens arrive within 24 hours of draw.

Necessary Information

Date of draw is required.

Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.

Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions: Send 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, we recommend that specimen draws be performed at the same time of day.

Specimen Minimum Volume The amount of sample necessary to provide a clinically relevant result as determined by the Laboratory.

1 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected


Mild OK; Gross reject


Mild OK; Gross reject




Secondary aliquot tubes

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperatures are also included.

Specimen TypeTemperatureTime
Whole Blood EDTAAmbient4 days