A solid phase fluorescent immunoassay for the quantitation of the C3 component of human complement

A non-competitive method for the determination of the C3 component of human complement in serum is described. This procedure involves use of a specific antibody covalently attached to derivatized polyacrylamide beads and a fluorescently labeled specific antibody. Reproducible results were achieved for C3 in serum in the range of 20 mg/d1 to 195 mg/d1 within 2 h. C3 levels as low as 125 ng/m1 can also be measured. Fluorescent immunoassay and radial immunodiffusion were used to determine C3 levels in healthy adults. Good agreement was found between the two methods.