PHYSICAL MODELS OF RADIOIMMUNOASSAY APPLIED TO THE CALCULATION OF THE DETECTION LIMIT

Conditions for maximal sensitivity of radioimmunoassay can be derived from simplified physical models. For competitive inhibition assay, physical models have been developed by Yalow and Berson and by Ekins et al. A simplified model for the sandwich assay and its implication with respect to the analysis of dose-response curves is presented in this paper. The models are applied to the calculation of the conditions for maximal sensitivity of the solid phase radioimmunoassay of human immunoglobulin A. The two models of competitive inhibition assay yield divergent results. The sensitivity under optimal conditions is better for the sandwich assay than for the inhibition assay. For the inhibition assay, experimentally obtained conditions for maximal sensitivity are compared with the predictions based on the models. The results of the calculations are discussed with respect to the application of physical models to the development of a radioimmunoassay in practice. © 1979, American Chemical Society. All rights reserved.