How B12 deficiency can impact on the individual and how society can impact on B12 deficiency.

Textbook knowledge is invaluable to both veteran and novice clinicians in that it provides the bedrock of common wisdom upon which one builds the edifice we call differential diagnosis. This commonalty of experience is further reinforced in grand rounds and ward rounds, and is also supported by adjunct procedures and laboratory tests that become inseparable from the diagnosis itself. Thus, in the case of the clinical diagnosis of vitamin B12 deficiency, which, like folate deficiency does not initially manifest itself clinically as a full-blown syndrome, the differential diagnosis is largely based on an abnormal laboratory finding ± macrocytic anemia. Macrocytic anemia, by virtue of decades-long experience, is known to be part and parcel of the deficiency state, yet recognition of the anemia as macrocytic is actually not the first stage clinically. First is the occurrence of anemia, second is the observation that the anemia is macrocytic; and only then does the suspicion of an underlying cobalamin or folate deficiency arise [1]. Thus, it is generally accepted that once there is evidence of macrocytic anemia, B12 or folate deficiency should be suspected, and this initiates the cascade of laboratory evaluations necessary to confirm the diagnosis.