Failure of long-term oral vitamin B12 therapy to replenish body B12 stores.
D000368:Aged; D000752:Anemia, Pernicious / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000032:analysis; D014805:Vitamin B 12 / Q000097:blood / Q000627:therapeutic use*
D014805:Vitamin B 12