Pernicious anemia: Early identification to prevent permanent sequelae

Pernicious anemia can be confidently diagnosed in a patient who has megaloblastic hematopoiesis, low serum cobalamin level, and impaired vitamin B₁₂ absorption correctable by administering intrinsic factor. Recent studies suggest that neurologic disorders in patients with pernicious anemia are less severe than in the past, highly responsive to therapy, and seen in the absence of anemia and macrocytosis. A low serum cobalamin level in the absence of anemia, particularly in a patient with a neurologic disorder, should not be ignored.