Superiority of the use of a pre-incubated complex of primary and second antibody in the radioimmunoassay of thyroid hormones

Abstract

We report on the superiority of a radioimmunoassay (RIA) system wherein the second antibody (Ab 2) is incorporated as a pre-incubated complex with the primary antibody (Ab 1) for the assay of haptens like triiodothyronine (T 3) and thyroxine (T 4). Separation of the antibody bound and free antigen (Ag) was accomplished by 8% polyethylene glycol (PEG) (final concentration) following a single incubation of less than 1 h. The other advantages of this system are a 15-fold reduction in the quantity of Ab 2 (without any need for increasing the concentration of PEG) and the consequent savings in cost.