Vitamin B 12 (Cobalamin) is a water-soluble vitamin and is normally found in animal products including meats, eggs, milk and milk products. It cannot be produced by the body and must be supplied by diet.
Vit B12 plays an important role in protein metabolism, DNA synthesis, formation of red blood cells and in maintenance of the central nervous system. A person can develop deficiency within weeks/months, when on a Vit B12 deficient diet.
It is necessary for hematopoiesis (formation of blood cells) and normal neural function.
An increase in the levels of Vitamin B12 is mostly due to excessive ingestion of multivitamin capsules with B 12. In case of a higher value look for cobalamin as a supplement component in any of the medicines that you are taking (many medicines have this as a constituent). Unlike some vitamins that are stored in fat tissues, vitamin B12 is water soluble. This means that if you consume more B12 than you need, the unneeded amounts of the vitamin leave your body through your urine.