Titer (titre) test
A blood test measuring existing antibody levels against a specific disease. Used to decide whether a vaccine booster is necessary.
Vaccine titer tests measure the antibodies in your pet's blood against core diseases (in dogs, parvovirus, distemper, hepatitis; in cats, panleukopenia, herpes, calici). If antibody levels are above a protective threshold, the pet is considered immune and a booster can usually be skipped that year.
Titer testing reflects a shift in best practice — modern core vaccines often produce immunity that lasts longer than the standard 1–3 year booster cycle. The World Small Animal Veterinary Association (WSAVA) endorses titer testing as an evidence-based alternative to routine boosters for core diseases.
Practical use: typical schedule is core vaccines as puppy/kitten, a 1-year booster, then titer test annually or every 3 years. Non-core vaccines (kennel cough, FeLV, lepto) require their own schedule based on lifestyle.
Cost is similar to a vaccine in many practices, sometimes slightly higher. The benefit is reduced lifetime vaccine load on the pet's immune system — particularly relevant in pets with previous vaccine reactions or autoimmune conditions.