Diagnosis
XLA diagnosis usually begins due to a history of recurrent infections, mostly in the respiratory tract, through childhood. The diagnosis is probable when blood tests show the complete lack of circulating B cells (determined by the B cell marker CD19 and/or CD20), as well as low levels of all antibody classes, including IgG, IgA, IgM, IgE and IgD.
When XLA is suspected, it is possible to do a Western Blot test to determine whether the Btk protein is being expressed. Results of a genetic blood test confirm the diagnosis and will identify the specific Btk mutation, however its cost prohibits its use in routine screening for all pregnancies. Women with an XLA patient in their family should seek genetic counseling before pregnancy.
Although the symptoms of a XLA and other primary immune diseases (PID) include repeated and often severe infections, the average time for a diagnosis of a PID can be up to 10 years.
Read more about this topic: X-linked Agammaglobulinemia