A solid phase radioimmunoassay for the detection of anti-insulin antibodies.

A solid phase radioimmunoassay for the detection of anti-insulin antibodies has been developed and evaluated. After coating round-bottomed wells of polyvinyl chloride with porcine monocomponent insulin, 50 microliters of serum from either insulin-treated diabetics or non diabetic controls was added to the wells, followed by the addition of 125I-protein A, and then the radioactivity of the bound 125I-protein A on the wells was counted. This solid phase radioimmunoassay is very simple, does not require centrifugal steps and the results correlated well with those of previously published immune precipitation methods (r = 0.68, p less than 0.01). Our present method requires only 50 microliters of serum and 4 hours for the assay, if the wells are coated with insulin in advance. Therefore, this procedure is thought to be suitable for clinical use.