Anne-Mette Hvas

Vitamin B12 deficiency is a major pub-lic health problem: however, there isno consensus on how to diagnose this deficiency. In the present review we attempt to give a balanced update. We include only issues related to diagnosing and treating vita-min B12 deficiency in the adult population and do not cover inherited diseases of vita-min B12 deficiency except for those related to classical pernicious anemia. From a fatal disease to a biochemical condition Classical pernicious anemia as described by Thomas Addison in the middle of the 19th century1 does not usually give substantial diagnostic problems. Patients with the rela-tively rare, archetypical disease have symp