Ordering 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.