Pernicious anemia is most frequently seen as an autoimmune disorder or is found in conjunction with other autoimmune disorders; it can also be seen in patients who underwent total or partial gastrectomy. There is often a strong genetic component to developing pernicious anemia. The more common form of pernicious anemia associated with autoimmunity and achlorhydria (lack of HCl secretion) often doesn't manifest until the fourth decade. A strictly genetic form has been seen in children younger than two years old.
Laboratory tests for pernicious anemia include previously mentioned tests and smear analysis. Still, the distinguishing feature is detecting anti-parietal cell antibodies (APCA) and/or intrinsic factor blocking antibodies (IFBA) in the patient's serum. Anti-parietal cell antibodies are seen in approximately 90% of patients at the initial diagnosis.
There are several methods for determining these antibodies; immunoassays are most commonly used.
