New diagnostic criteria for common variable immune deficiency ( CVID ), which may assist with decisions to treat with intravenous or subcutaneous immunoglobulin

Summary C ommon variable immune deficiency ( CVID ) is the most frequent symptomatic primary immune deficiency in adults. The standard of care is intravenous immunoglobulin ( IVIG ) or subcutaneous immunoglobulin (sc IG ) therapy. The cause of CVID is currently unknown, and there is no universally accepted definition of CVID . This creates problems in determining which patients will benefit from IVIG /sc IG treatment. In this paper, we review the difficulties with the commonly used E uropean S ociety of I mmune D eficiencies ( ESID ) and the P an A merican G roup for I mmune D eficiency ( PAGID ) definition of CVID . We propose new criteria for the diagnosis of CVID , which are based on recent scientific discoveries. Improved diagnostic precision will assist with treatment decisions including IVIG /sc IG replacement. We suggest that asymptomatic patients with mild hypogammaglobulinaemia are termed hypogammaglobulinaemia of uncertain significance ( HGUS ). These patients require long‐term follow‐up, as some will evolve into CVID .