https://doi.org/10.1351/goldbook.13745
Reciprocal of the highest dilution of a titration of an antigen with an antibody that gives a measurable effect (e.g., agglutination), and thus an empirical measure of the avidity of an antibody.
Example: If the effect is seen until a dilution of \(\pu{1\!{:}\! 1000}\), the antibody titer is \(\pu{1000}\).