A titer test (pronounced TIGHT er) is a laboratory test measuring the existence and level of antibodies to disease in blood. Antibodies are produced when an antigen (like a virus or bacteria) provokes a response from the immune system. This response can come from natural exposure or from vaccination.
It is a simple blood test but is expensive when sent out to a lab. Cost can run from $70 to $120 and up. (click HERE to read of less expensive in-house tests)
It is still controversial, test results are felt to be open to interpretation and not always accurate. Do not expect that everyone will accept test results in place of proof of vaccination. Test results will NOT be accepted by Animal Control and most others as a substitute for vaccination of healthy dogs as required by law.
AAHA vaccine guidelines say that titer testing is an appropriate way to check for immunity to parvovirus, distemper and adenovirus. However, it is not recommended for canine leptospirosis, bordetella or Lyme disease, because these vaccines only provide short-term protection.
Do your own research, consult with your vet and advocate for your dog!