immunology allergic disorders
Selective IgA Deficiency
Diagnosis of Selective IgA Deficiency
Measurement of serum Ig levels Measurement of antibody response to vaccine antigens Diagnosis of selective IgA deficiency is suspected in patients who have recurrent infections (including giardiasis), anaphylactic transfusion reactions, or a family history of Common Variable Immunodeficiency (CVID) (CVID), IgA deficiency, or autoimmune disorders or who are taking drugs that lead to IgA deficiency. Suspected patients should have immunoglobulin levels measured; diagnosis is confirmed by a serum IgA level<7 mg/dL (< 70 mg/L, 0.4375 micromol/liter ) with normal IgG and IgM levels. IgG antibody titers are measured before and after administration of vaccine antigens; patients should have a normal rise in antibody titers ( ≥ 2-fold increase in titer at 2 to 3 weeks). Testing of family members is not recommended because most patients with low IgA have no clinically significant manifestations. However, patients who have a history of transfusion-related reactions should be tested for IgA deficiency, particularly if they have a family member with IgA deficiency. 