Iterative weighted regression analysis of logit responses: a computer program for analysis of bioassays and immunoassays.

A program, WRANL, is described for the analysis of immunoassays or bioassays which have a logistic dose-response relationship. Responses are transformed to logits and iterative weighted regression analysis is used to obtain log dose-logit response lines for all preparations compared in an assay. Potency estimates of preparations relative to the standard preparation are available for both unweighted and weighted regression analyses together with detailed analysis of variance, estimates of slope and other relevant parameters. The general comparisons of dose-response relationships produced by the program are a feature of particular interest. However, an option which suppresses the more general output is available if the program is to be used for analysis of a 'screening' assay comparing single dilutions or doses of test samples with a standard curve. Data input is designed to permit immediate running of the program by junior personnel. Data output is designed to facilitate record keeping.