Nephelometry of human IgG subclass concentration in serum

An immunoassay method for determination of human IgG subclass concentration by rate nephelometry was developed by using the Beckman Immunochemistry Analyzer, subclass-specific antisera, and a human serum standard. Twelve sera derived from normal as well as gammapathological patients were analyzed. The total IgG concentration, as determined by using a readily available kit, correlated with the sum of the concentration of the individual subclasses. Most of the gammapathological cases were shown to be the IgG1 subclass, which was confirmed by radial immunodiffusion.