A comparison of methods for the rapid quantitation of unsaturated transcobalamin II and the R-binding proteins

Methods for the rapid quantitation on unsaturated transcobalamin II (TC II) and R-binders in serum following separation of these binders using a) adsorption by uncoated charcoal, b) adsorption by Quso G32, c) precipitation with ammonium sulphate, and d) acidification of serum, have been compared with the standard gel filtration technique. In serum from healthy subjects and patients with elevated R-binders, the serum acidification and Quso methods yielded results in closest agreement with those obtained by gel filtration. When TC II was markedly elevated, the recommended concentration of Quso failed to remove all TC II from serum. Both the serum acidification and Quso methods are suitable for routine use, providing that with the latter method the concentration of Quso is increased when elevated levels of TC II are anticipated, as, eg, in severe jaundice. All the rapid methods tested yielded clinically significant results in patients with myeloproliferative disorders.