title: A useful method for determining class-specific rheumatoid factors with computerized analyses of data.
abstract: A simple and sensitive enzyme-linked immunosorbent assay (ELISA) was developed to determine rheumatoid factors (RFs) of IgG, IgA and IgM class. Standardisation was performed with a standard reference serum for IgM-RF, calibrated according to the WHO preparation, and with the serum of a patient containing high levels of IgA- and IgG-RF. The sigmoidal shaped calibration curve was fitted with a computerized four parameter logistic model with simplified mathematical computations. This method provided to be more accurate for measuring RF levels, as judged by the smaller residuals, than logit or log-linear transformations. The considerable reduction in processing time, which is obtained by the computerized analysis of data, makes this method of class-specific RF determination suitable for routine analysis.
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D010434:Pepsin A; D012217:Rheumatoid Factor / Q000032:analysis*; D012984:Software
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012217:Rheumatoid Factor; D010434:Pepsin A