Antibodies against Intrinsic Factor (Castle's Factor, AIFA)

Purpose of testing antibody levels against intrinsic factor

This test is most commonly used in the diagnosis of malignant anemia (Addison-Biermer disease), which is associated with vitamin B12 deficiency caused by a lack of intrinsic factor in the stomach. The presence of antibodies to the intrinsic factor may indicate an autoimmune origin of the disease.

When is it worthwhile to test for intrinsic factor antibody levels?

• Symptoms of megaloblastic anemia (fatigue, weakness, pale skin).
• Symptoms of megaloblastic anemia (fatigue, weakness, pale skin).
• Neurological symptoms, such as tingling in the limbs, balance or memory problems.
• Diagnosis of vitamin B12 deficiency.
• Suspected pernicious anemia.

Preparation for intrinsic factor antibody test

No special preparation for the test is required. It can be performed at any time of the day, regardless of meals.

Interpretation of the results of the intrinsic factor antibody test

• Positive result - indicates the presence of antibodies against intrinsic factor and may indicate malignant anemia.
• Negative result - absence of antibodies, however, does not completely rule out malignant anemia. In this case, additional diagnostic tests may be necessary.

Considerations for testing intrinsic factor antibody levels

The test result should always be interpreted by a physician in the context of clinical symptoms and the results of other laboratory tests.