How is pernicious anemia/vitamin B-12 deficiency diagnosed?
The first step is always a thorough history and physical examination by a health care practitioner. The results of this examination are used to help direct further testing. A number of laboratory tests are available that can help diagnose pernicious anemia as well as other causes of vitamin B-12 deficiency. These tests include: • A complete blood cell count (CBC) • Examination of a blood smear (peripheral smear) under a microscope, often performed in association with a CBC • Blood vitamin B-12 level measurements • Tests for the presence of autoantibodies to intrinsic factor or stomach lining cells • Blood levels of iron and iron-binding capacity • Folate levels (which are often reduced when vitamin B-12 levels are low) • Blood levels of methylmalonic acid or homocysteine, both of which may be sensitive indicators of vitamin B-12 deficiency • The Schilling test, a measure of how well the body can absorb vitamin B-12, is less commonly used today than in the past. • Finally, bone marrow a
