When suspected, the diagnosis can be confirmed by laboratory measurement of IgA level in the blood. SIgAD is an IgA level < 7 mg/dL with normal IgG and IgM levels (reference range 70–400 mg/dL for adults; children somewhat less).
Selective immunoglobulin A deficiency
Isolated primary immunoglobulin M deficiency
Primary immunodeficiency
IgG deficiency
X-linked agammaglobulinemia
Transient hypogammaglobulinemia of infancy
Chronic granulomatous disease
Combined immunodeficiencies