VITAMIN B-12 ACTIVE

Overview

Plasma vitamin B-12 is bound to 2 proteins, transcobalamin and haptocorrin . Transcobalamin carries a minor part of the circulating vitamin B-12, which is the active part and is available for cells.Haptocorrin on the other hand is almost fully saturated with vitamin B-12 , but this is not available for cells, thus considered as an inactive form of the vitamin B12 .As a result measurement of holoTC would be more clinically meaningful than measurement of total vitamin B-12. The metabolites HOMIOCYSTEINE and Methyl Malonic Acid also mirror any lack of vitamin B-12 within the cells. Both plasma tHcy and MMA accumulate in vitamin B-12-deficient patients.