Titre tests are a laboratory test to measure the level of something in the blood, in this case the levels of antibodies to the common viral diseases in dogs and cats
Titre tests are a laboratory blood test that determines the level of antibodies (disease fighting proteins produced by the immune system) to a given disease-causing virus in the body. It is expressed as a dilution. This means that the antibody level is measured in the sample as it came from the dog, then diluted in half, then in half again, and so on until the antibody level cannot be detected. The titer is the lowest dilution of the blood sample in which antibodies can be measured. A high titre is one in which antibodies can be measured in a very dilute sample. We know that a dog is immune to a disease if he has a certain level of antibodies, and we use the expression “protective titre” to mean enough antibodies are present to fight off disease
Today I wanted to discuss more how often they need to be done, when to start the regime and recent updates. But first let me go through the advantages and benefits of titre testing.
Why titre test?
Most vets agree that vaccines are necessary but the frequency in which they are administered is often debated. In particular, the recommendation to administer core vaccines to adult dogs and cats at 3 year intervals (or longer) rather than annually resulted in differences of opinions among veterinarians.
It has now been shown that duration of immunity after vaccination with Modified Live Virus vaccines for most animals will be many years or a lifetime, based on challenge and serological studies (Schultz et al. 2006)
and expanded upon in 2010 (Schulz, R.D. (2010). Duration of Immunity for canine and feline vaccines: A review. Veterinary Microbiology)
. If an animal already has a protective level of immunity, revaccination will not be required.
In my practice we use VacciCheck a rapid and affordable option to check the titre levels for the core diseases that are vaccinated against. It provides easy to interpret results which determine whether the animal has a protective level of immune response or whether they need revaccination.
This is supported by the World Small Animal Veterinary Association (WSAVA) Guidlines, which state that an animal that returns a positive titre has a protective level of immunity and therefore does not require revaccination.
There are a number of ways VacciCheck can be beneficial to determine a dog or cat’s antibody titre levels of the 3 core diseases:
- To determine when it is optimal to end the vaccine series
- After a puppy (or kitten) vaccination to indicate immunisation success was achieved
- To determine if a booster is required
- To ascertain existing protection for a lapsed dog or cat vaccination program
- To test a stray/abandoned animals with no clinical history
- To test animals on immunosuppressant treatment
- Can be used as part of an annual health check program
- Can help with minimising the risk of adverse effects of vaccinations reducing the risk of over-vaccination consequences
In my experience there are two ways in which titre tests are not being used as they should be:
- In Puppies shortly after vaccination to check if they are proctected
- More controversially, when you have a positive result to a titre test one does not need to repeat it a year or even 3 years later.
1. Puppy & Kitten tests at 4-5 months
I advocate a titre test for all puppies around 3-4 weeks after the last puppy vaccination to check that it has worked. The reason is, studies have shown that a percentage of puppies – up to 10% in some depending on the age it is done to a large extent – do not demonstrate antibodies in particular to CPV.(Canine ParvoVirus) So are they protected? Probably not, and so a revaccination at this point is indicated.
Because of this problem (thought to be caused by excessive levels of maternal antibodies stopping the vaccines working but there may well be more to it as certain breeds are more highly represented) some practices are recommending a 3rd puppy vaccination for CPV at 16 weeks.
I am putting it to you that a titre test at this point would be best practice and yet is infrequently if ever recommended by vets or advocates of tire testing from the alternative medicine advocates.
2. When should you repeat your test?
If you believe what immunologists such as Dr Schultz tell us – see the references in paragraph 2 above – then protection is life long.
If your dog has once had a positive titre test then her immune system has responded to vaccination (or natural exposure) to disease and immunity is produced. Even if antibodies cannot be demonstrated in a titre test there is a cell mediated immunity induced which we cannot readily measure with a antibody titre test only by using exposure studies as in the research above.
These studies are expensive to run and welfare considerations make them unpopular and so numbers are small and perhaps not really good studies?. It is not really in the vaccine manufactures interests to prove their product last for say 9 years as they sell less one could cynically say but they do last for years. I have tested dozens perhaps hundreds of dogs over the past few years and see very few titre results reducing significantly with age.
And this is the point where most vets and their guardians lose their way when it comes to fully understanding titres.
There are three key points to remember:
1. Repeating titres yearly is a waste of money
2. Repeating titres every three years is not necessary
3. Re-vaccinating a dog who has previously titered as protected, but now tests below the minimum is unnecessary
You do NOT need to vaccinate a dog if his titre falls from the protected to the low range – because he still has memory cells!
The typical dog whose titre falls below threshold is the healthy senior dog, who stays at home and has little exposure to any diseases. It would be a waste of his body’s energy to keep producing antibodies to viruses he was not being exposed to. So, his circulating antibody level falls. Should he be exposed to a virus, his immune system will begin to make antibodies with the information encoded in the memory cells. And he will be protected against the disease in question. (Note: I am speaking of a normal dog – dogs with immunosuppressive diseases or neoplasia may be at risk for contracting disease, and decisions regarding vaccination for them must be made on an individual basis.)
Leptospirosis what to do about this vaccine/ disease.