An enzyme-linked immunosorbent assay (ELISA) for the determination of diphtheria toxin antibodies.

An enzyme-linked immunosorbent assay (ELISA) for the quantitation of diphtheria toxin antibodies is described. When the ELISA technique was compared to a single radial immunodiffusion assay the results correlated well but the ELISA technique was ten thousand times more sensitive. It was also at least ten times as sensitive as the in vivo rabbit skin test.