Antibody-based assays such as the Virus Neutralisation Test (VNT) and ELISA are the most commonly used for both laboratory diagnosis of FMD and determining the most appropriate strain.

FMDV induces a range of antibodies of differing specificities and functional properties. Many of these antibodies only recognise whole virus particles.

The VNT measures antibodies which bind to intact FMDV particles and inhibit the infection process in susceptible cells. For this reason virus neutralising antibody titres are considered the most relevant to protection.

ELISA is considered to measure most antibodies which bind to virus (including non-neutralising antibodies) and generally correlates well with the VNT. Occasionally, this correlation does not hold, probably due, to unusual relative proportions of neutralising and non-neutralising antibodies with some vaccinated animals.