Removal of background interference in nephelometric determination of serum proteins.

By precipitation of beta-lipoprotein by a dextran sulphate and calcium chloride mixture the background light scattering in continuous flow nephelometric systems can be reduced to such a level that it can be neglected in practice. No loss of IgG, IgA, IgM, orosomucoid or transferrin on precipitation could be demonstrated. The supernatant could not be used for immunoelectrophoresis or radial immunodiffusion in analysis of these proteins since significantly lower values were obtained for some of them than in native serum.