Intrinsic Factor Blocking Antibody

Intrinsic Factor Blocking Antibody is an autoantibody that blocks the binding of vitamin B12 to intrinsic factor, preventing B12 absorption in the small intestine. This antibody is highly specific for pernicious anemia, an autoimmune condition that causes B12 deficiency. Positive results indicate autoimmune-mediated B12 malabsorption, which requires lifelong B12 supplementation (typically injections or high-dose oral). This test is used alongside parietal cell antibody and B12/MMA levels to diagnose pernicious anemia.