Three of the four core vaccines have in-house tests to measure titer levels (measures the level of antibodies in a blood sample) which in turn tells the Doctor if your pet has immunity (protection) against a particular disease(s). We strongly recommend these tests either after the initial puppy/kitten series to determine with relative certainty that your pet is protected. Or, during their annual preventative care visit. Why? Because if they have sufficient immunity then there may not be a need to vaccinate. At Vets to Pets we have moved away from automatically vaccinating on an annual basis. We certainly don’t want to over or under vaccinate. Discuss this issue with Dr. Zafir during his next visit.