Patterns of plasma cobalamins in control subjects and in cases of vitamin B₁₂ deficiency

A method for thin-layer chromatography and bioautography of plasma cobalamins is described. It requires only 5 ml of blood. Results are reported in 35 healthy people and hospital controls, and in 14 cases of untreated pernicious anaemia. In the control group there were two major components, methylcobalamin and a component which is probably a mixture of hydroxocobalamin and deoxyadenosyl cobalamin. Many cases of untreated pernicious anaemia showed a characteristic pattern in which methylcobalamin was reduced in relation to hydroxocobalamin. This pattern was also seen in one vegan who was taking a diet without B(12) supplement. A minority of subjects showed traces of cyanocobalamin; this compound was not confined to smokers. The significance of the results and possible diagnostic utility of the technique are discussed.