Antibody testing for vaccine-preventable diseases
The demand for and availability of antibody testing (both qualitative and quantitative) for canine vaccine preventable diseases has increased substantially over the past decade.
It is imperative, when assessing test results, that the veterinarian have a clear understanding of the indications for testing and the interpretation of test results.
This section specifically addresses indications and interpretation with respect to canine distemper virus (CDV), canine parvovirus (CPV), and canine adenovirus (CAV) antibody only.
Antibody testing for the purposes of determining protection from infection is valid only for CDV, CPV, and CAV.
See the following FAQ sections for more information on interpreting antibody tests for:
NOTE: In most States, a veterinarian does NOT have discretion to waiver rabies vaccination in patients with an existing or prior health disorder that, in the veterinarian’s opinion, should preclude vaccination. Only a limited number of States give a licensed veterinarian the authority to issue a point-of-care waiver for rabies vaccine. See: www.rabiesaware.org
- Results reported as a titer (e.g., 1:1600).
- Methodology: a laboratory-based, "end-point" test.
- Generally more sensitive than qualitative tests.
- Results usually reported within days.
- Measures functional ability of antibody to neutralize live virus
- Results reported as “yes” (POSITIVE) or “no” (NEGATIVE).
- Methodology: in-hospital, point-of-care test kit.
- Good correlation with “positive” quantitative test results.
- Results available within 25 minutes.
Key points:
- A “positive” test result correlates with protection from infection if exposed.
- A “negative” test result does not always correlate with susceptibility.
- Antibody may fall below detectable levels in the absence of exposure, including re-vaccination. For adult dogs which have been shown to have had protective titers against CDV, CPV and CAV2 in the past, exposure to pathogenic virus is likely to induce an immune “memory” response resulting in a rapid, anamnestic protection, even years following the last vaccination.
- A“negative” or "weak" response indicates that further vaccination may be of benefit to re-establish humoral response above the sterile immunity threshold.
- In effect, documentation that an individual patient has ever had a “positive” antibody test result for canine distemper, parvovirus, and/or adenovirus denotes that immune memory exists and the patient, if exposed, is expected to mount a rapid, protective response whether or not detectable levels of antibody were present at the time of the exposure.
- False negative test results are uncommon and can be associated with low test sensitivity, insufficient time following vaccination for a detectable antibody response to develop, procedural errors, etc.
Interpreting the significance of a “positive” versus “negative” test result is largely dependent on the test indication.
Testing indications
Listed below are specific indications for serologic testing (canine distemper, parvovirus, and/or adenovirus) in clinical practice.
For each INDICATION listed, an algorithm is included that addresses the interpretation of the POSITIVE vs NEGATIVE test result and recommendations for PATIENT MANAGEMENT:
Click on the list of indications below:
ADULT dog - DUE or OVERDUE for a booster
To assess the immune status of an ADULT dog that is DUE or OVERDUE for a booster
Example: indicated when testing is requested by a client concerned over potential risks associated with over-vaccination.
ADULT dog - of ADVANCED AGE or with UNIQUE HEALTH PROBLEMS
To guide decisions on revaccination in dogs of ADVANCED AGE or with UNIQUE HEALTH PROBLEMS
ADULT dog - UNKNOWN or UNDOCUMENTED vaccination history
To assess the immune status in an adult dog when the vaccination history is unknown or cannot be document
Example: indicated to establish evidence of prior vaccination in a recently adopted adult, stray dog.
PUPPIES - upon completion of the INITIAL VACCINATION series
To assess the immune status following completion of the initial vaccination series in PUPPIES
Example: testing is indicated when a client plans to travel with a young dog for show or sale purposes – or – when seeking assurance that a pup is, in fact, protected following completion of the initial series.
NOTE: Testing is NOT RECOMMENDED until at least 2 weeks following administration of the last vaccine dose in the initial series. Veterinarians should check the label for diagostics as some are labelled for use in puppies >24 wk of age or greater. Quantitative methods may be used at 17-18 wk of age, and when maternal antibody levels are known, puppies may be tested at even younger ages.
PRE-BREEDING - to assess the immune status of a bitch
To assess the immune status of a bitch prior to breeding
Example: owner requests a pre-breeding booster with core vaccines to assure the bitch will transfer protective levels of maternally derived antibody to nursing pups.
NOTE: specialists in canine reproduction generally do not support the concept of administering a pre-breeding booster to assure immunity in newborn pups. Reason: it is not clear that doing so will, in fact, result in higher levels of Maternally Derived Antibody (MDA) in new-born pups. In addition, achieving higher levels of MDA could conceivably result in extended periods of MDA-interference as the initial series of core vaccines is administered. However, titer testing before or during pregnancy can identify litters that may benefit from supplemental antibody administration in high risk situations.
NON-RESPONDER - to identify dogs INCAPABLE of producing PARVOVIRUS antibodies
To identify a genetic "non-responder" (i.e. dogs that are incapable of producing parvovirus antibodies following vaccination.)
NOTE: Recognized throughout the world, a small number of dogs (1 in 1000, unconfirmed estimate) are genetically incapable of mounting protective levels of antibody following parvovirus vaccination (although they respond well to all other vaccine antigens). As a result, these dogs remain susceptible to parvovirus infection if exposed despite having received several doses of vaccine. Genetic “non-responders” and “low-responders” are at high risk for infection if exposed. Knowing this information about an individual is helpful for guiding lifestyle and clinical decision-making.
SHELTER DOGS - to assess the immune status of the population
To assess the immune status among a population of shelter-housed dogs
Example: knowledge of the immune status of dogs at high risk for exposure, co-housed within a defined facility, enables identification of susceptible vs. protected dogs in the event a disease outbreak occurs
Boehringer Ingelheim USA Inc., Merck Animal Health, and Zoetis.
