An antibody titre test is a blood test that determines the concentration (titre) of antibodies in the blood. Antibodies, also called immunoglobulin, are used by the immune system to fight off pathogens such as viruses or bacteria. A high antibody concentration (high antibody titre) indicates either: recent exposure to a pathogen, or immunization is up to date.

Titre testing can be used to customize vaccination schedules to fit the needs of the individual patient. For those concerned about vaccine reactions or overvaccination, titre testing can be used to determine if a patient has immunity to a disease and it revaccination is required.