Screening for parietal cell antibodies (anti-parietal cell antibodies, APCA) antibodies is used to evaluate patients suspected of having pernicious anemia or immunological etiology of vitamin B12 deficiency with or without megaloblastic anemia. The presence of antibodies against parietal cell antibodies results in the disruption of the production of endogenous factor (IF) by these cells. This leads to pernicious anemia due to the autoimmune process. Thus, APCA testing is used to evaluate pernicious anemia. APCA antibodies may be elevated in atrophic gastritis and in some other autoimmune conditions.
What Do Pathological Values Mean?
- Increase: Atrophic gastritis, autoimmune pernicious anemia, diabetes mellitus, gastric cancer, gastric ulcer, thyroid diseases
More information on Pernicious Anemia
Pernicious anemia is characterized by atrophic gastritis and is the end state of a progressive disease known as autoimmune chronic atrophic gastritis. In this disease, the immunological etiology of inflammation results in the destruction of the gastric parietal cells resulting in the inability to produce endogenous factor and the inability to absorb dietary vitamin B12. Diagnosis of pernicious anemia includes the presence of macrocytic anemia in the context of vitamin B12 deficiency as well as the documentation of the presence of autoantibodies and in particular of anti-parietal cell antibodies (APCA) and antibodies against endogenous factor (IFA). APCA antibodies bind to the alpha- and beta-subunits of the membrane-bound ATPase H+/K+ (hydrogen ion pump). In contrast, IFA antibodies directly bind the endogenous factor, blocking its ability to bind vitamin B12. Both APCA antibodies and IFA antibodies are useful diagnostic markers for pernicious anemia.
The presence of APCA antibodies has 81% sensitivity and 90% specificity for the diagnosis of atrophic gastritis, while the presence of IFA antibodies has 27% sensitivity and 100% specificity. Combining APCA and IFA antibody screening is the best practice for the evaluation of patients with suspected pernicious anemia.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
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