B-Cell Phenotyping Profile for Immunodeficiency and Immune Competence Assessment, Blood

Casandra

Casandra Test Code MC51421Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID IABCSCPT Codes 86355, 86356, 86357, 86359, 86360

B-Cell Phenotyping Profile for Immunodeficiency and Immune Competence Assessment, Blood

Clinical Use

Use

This test is used for screening common variable immunodeficiency (CVID) and hyper-IgM syndromes. It also assesses B-cell subset reconstitution following stem cell or bone marrow transplant and the response to B-cell-depleting immunotherapy. CVID is the most common primary immunodeficiency characterized by hypogammaglobulinemia and impaired functional antibody responses, often with recurrent sinopulmonary infections. The test helps in diagnosing hyper-IgM syndromes, which feature defective isotype class-switching and reduced class-switched memory B cells. This test is not suitable for evaluating lymphoproliferative disorders such as leukemia, lymphoma, and multiple myeloma.

Special Instructions

Two separate whole blood EDTA specimens are needed: one to be shipped ambient and the other refrigerated. The TBBS test is automatically performed when ordering this panel. If only one specimen type is received, specific test components may be canceled or adjusted. Proper timing and consistency in specimen collection are crucial, especially for serial monitoring. Specimens are recommended to arrive at the lab within 24 hours of collection to ensure accuracy.

Limitations

This assay's results are based on B cells from the mononuclear cell fraction of peripheral whole blood, which may differ from whole blood assays. Timing and consistency of blood collection time are critical for reliable monitoring of lymphocyte subsets. The test's accuracy might be affected if specimens are not received by Friday at 8 p.m. Central Time as tests are not conducted on weekends or observed holidays.

Test Details

New York Approved