A Ligand-Binding Assay for Thyroxine-Binding Globulin Based on Polyethylene Glycol Separation

Abstract

A simple ligand-binding assay for thyroxine-binding globulin (TBG) is described. The method depends on the partition of labelled thyroxine between bovine serum albumin and TBG. Differentiation between labelled thyroxine bound to TBG and bovine serum albumin is achieved by the addition of excess TBG antiserum and subsequent precipitation with polyethylene glycol. The results are compared with the Corning Immophase kit method for TBG.