A simple method for the separate measurement of transcobalamins I, II, and III: normal ranges in serum and plasma in men and women.

A simple method for the separate measurement of the unsaturated binding capacity of the three main circulating vitamin B12 binders, transcobalamins (TCs) I, II, and III, is described. The method involves batch separation of TC I and III from TC II by means of Quso G32, followed by batch separation of TC I from TC II with the use of diethylaminoethyl. The present study provides the first complete comparison of unsaturated TC I, II, and III in serum versus fluoridinated plasma of a single group of normal men versus women. There are consistently higher values in serum, largely due to an in vitro increment of TC III, prevented by NaF. The results are compared with values for some of these parameters obtained by others with the use of different methods, providing a standard for evaluating significance of results by various methods.