Electroimmunodiffusion (EID): a simple, rapid method for quantitation of immunoglobulins in dilute biological fluids.

Abstract

Abstract An immunoprecipitation method called electroimmunodiffusion (EID) is described in which antigen diffuses, under the influence of an electric field, into a layer of agar containing specific antiserum. The antigen-antibody precipitate length is proportional to the concentration of antigen in the well, and to the duration of electrophoresis. The method is rapid, accurate, and reproducible, and requires 4 μL of sample. EID is more sensitive than simple radial diffusion. The lower limits of accurate quantitation are γG, 0.2 mg. per cent; γA, 0.5 mg. per cent; γM, 0.8 mg. per cent. The method is suitable for the measurement of immunoglobulins in small samples of dilute and unconcentrated biological fluids. Conditions for the measurement of γG-globulin in cerebrospinal fluid (CSF) are described. Normal CSF contained 1.0 to 3.1 mg. per 100 ml. γG.