Common variable immunodeficiency (CVID) is a rare immune deficiency characterized by low levels of serum IgG, IgA, and/or IgM, with a loss of Ab production. The diagnosis is most commonly made in adults between the ages of 20 and 40 years, but both children and much older adults can be found to have this immune defect. Continue reading “Diagnostic Criteria for Common Variable Immunodeficiency (CVI)”