B-Cell CD40 Expression by Flow Cytometry, Blood

Casandra

Casandra Test Code MC25392Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID 89009CPT Code 88184

B-Cell CD40 Expression by Flow Cytometry, Blood

Clinical Use

Use

This test is useful for evaluating patients suspected of having hyper-IgM type 3 (HIGM3) syndrome, which is associated with defects in the CD40 gene. The test can also assess B-cell immune competence in various clinical settings, such as autoimmunity, malignancy, and transplantation. Homozygous variants in the CD40 gene cause autosomal recessive hyper-IgM syndrome type 3, which is typically observed in patients younger than 10 years. It is vital for distinguishing between forms of hyper-IgM syndrome due to differing prognoses and potential treatment options, such as intravenous IgG and hematopoietic cell transplantation.

Special Instructions

This test is not used to detect CD40L expression (CD154) associated with X-linked hyper-IgM syndrome. For shipment, specimens must arrive within 24 hours of collection, ideally on weekdays, as specimens received on weekends or holidays may be canceled. Ordering requires the healthcare professional's name and phone number.

Limitations

The assay does not detect CD40L expression (CD154), which is responsible for X-linked hyper-IgM syndrome. Therefore, for X-linked hyper-IgM syndrome assessment, a different test should be selected. Testing is dependent on proper specimen handling and transport conditions; delays beyond 24 hours from collection to lab receipt can lead to specimen rejection.

Test Details

New York Approved