Development and validation of radioligand binding assays to measure total, IgA, IgE, IgG, and IgM insulin antibodies in human serum.

Radioligand binding assays for total and Ig classes of insulin antibodies (IAB) were developed and validated. For each assay, insulin-extracted serum samples were incubated with radiolabeled insulin in the presence and absence of high levels of unlabeled insulin to determine nonspecific binding and total binding, respectively. To measure total IAB, antibody-bound insulin was precipitated with a polyethylene glycol solution, washed, and counted in a gamma-counter.