An assessment under routine conditions of an immunoelectrophoretic assay for thyroxine-binding globulin.

The correct clinical interpretation of serum total thyroxine requires a knowledge of the thyroxine binding globulin (TBG) concentration. An immunoelectrophoretic method for TBG assay has been assessed under routine conditions for precision, sensitivity and recovery. TBG has been compared with T3 Resin Uptake for euthyroid subjects, and patients with myxoedema and thyrotoxicosis. The relationship between TBG and age has also been studied. The method proved to be reliable, sensitive and a technically simple method for the routine determination of TBG and an excellent replacement for the indirect T3 Resin Uptake Test.