Determination of immunoglobulin A in saliva by immunobead enzyme-linked immunosorbent assay: comparison with single radial immunodiffusion.

For the quantitative measurement of immunoglobulin A in human saliva, an immunobead enzyme-linked immunosorbent assay was investigated in detail. The method proved to be fast and sensitive, and it gave reproducible results. There was a strong correlation with results obtained by a single radial immunodiffusion method. The immunobead method gave 1.8 times higher values than the single radial immunodiffusion method with a lower correction factor for low-immunoglobulin A saliva and a higher factor for immunoglobulin A-rich saliva.