Abstract: A process and test kit for the quantitative determination of the individual and total unsaturated Vitamin B-12 binding capacities of the three transcobalamins TC-I, TC-II, and TC-III in serum. The process comprises incubating a serum sample with a solution of .sup.57 Co Vitamin B-12, contacting the resulting mixture with a TC-II adsorbent and with a DEAE-cellulose adsorbent for TC-I and TC-III, measuring the total radioactivity adsorbed to said adsorbents, selectively desorbing TC-III from the DEAE-cellulose adsorbent by washing with a monopotassium phosphate solution of about 0.05 M and at a pH of about 4.6, measuring the individual radioactivity adsorbed to each of said adsorbents, and calculating the radioactivity that had been washed from the DEAE-cellulose adsorbent by said phosphate solution. The resulting four radioactivity values are functions of the total, TC-II, TC-I, and TC-III unsaturated Vitamin B-12 binding capacities, respectively, of the serum tested.

Abstract: A process for the quantitative determination of the transcobalamins TC-I, TC-II, and TC-III in serum. The process comprises incubating the serum with radiolabeled vitamin B-12, passing the resulting mixture through adsorption means, such as a charged cellulose filter or equivalent mini-column, for TC-II at a pH of about 8.5, adsorbing the remaining TC-I and TC-II components on a DEAE-cellulose type adsorbent, selectively desorbing the TC-III component with monopotassium phosphate solution of about 0.05 M and pH of about 4.6, and determining the radioactivity of each of the three transcobalamin fractions to indicate the individual and total unsaturated vitamin B-12 binding capacity of the three transcobalamins in the serum sample tested.