Titre testing and immunity

When you do a titre test, the antibodies for the 3 basic core diseases are checked (Distemper, Hepatitis (Canine Adenovirus) & Parvovirus).

The level of circulating antibodies are then scored, with Vaccicheck these range from 0-6, with 6 being the strongest level of antibodies and 0 being the least.

Officially, provided a dog has a score of 1-6 for each disease, they have a protective level of antibodies recorded, but it's not that simple. Dogs (and all other animals) have 2 types of immune system - the humoral system, which is what is being checked when a titre test is performed and the mediated immune system, which is basically the part of the immune system that has long term memory of diseases and can quickly instruct the humoral immune system to produce antibodies when a threat is detected.

The titre test only checks antibodies produced by the humoral immune system, so to have a 'score', there has to be antibodies circulating at a high enough level to be detected. In an older dog (ie not a puppy), it is quite possible that a dog may be protected against a disease, but because the immune system has not recently been 'threatened' by a disease, there are no circulating antibodies in the system. A titre test may therefore record a score of '0' indicating that a 'booster' is required, but in fact the dog has perfectly adequate protection against that disease, but it is currently dormant, due to no present threat. It is unfortunately not possible to check the mediated immune system with a titre test, so this test will never be as accurate as people mistakenly think it is.

Think of the humoral immune system as being a fire engine - when there is a fire, the fire engine is despatched from base to deal with the fire, it is not constantly driving around the streets hoping to find a fire in progress.

The immune system works in a similar way, it is dormant until a threat is detected, then antibodies are rapidly produced to deal with the intruders. When a titre test is done, it is very common that the Distemper level is recorded as '0', as there is almost no Distemper in the environment nowadays, and therefore the dogs immune system is not circulating antibodies against the disease. This does not equate to zero immunity!

The best use of a titre test is within a couple of months of a puppy being given its vaccinations. A strong immune response would be expected to confirm a protective level of circulating antibodies.


With thanks to Paul Seamons (Messano Golden Retrievers) for allowing me to reproduce this article


The most useful time to run a titer test is after your puppy has received her initial series of vaccinations. Especially if you’ve limited that series to just one or two vaccinations, the last being after 16 weeks of age. The odds are you’ve just conferred lifetime immunity to your youngster.

Note: If you vaccinate your pup at six weeks of age, or even younger, there’s about a 50:50 chance that no immunity will result to distemper or parvovirus as mum’s colostrum has given your puppy antibodies against both, and those antibodies are preventing the vaccine from stimulating his own immunity. Mum’s protection is temporary though, hence the need for long term protection.

If you want to know how effective your vaccinations were in conferring immunity (i.e. did vaccination = immunization?), ask your vet to run a titer test a few weeks later. If there’s any measurable titer to the disease in question, your puppy has actively made immunity to the viruses. It doesn’t need to meet some standard of “protective” to be useful, it just has to be positive.

Testing yearly will eventually show titers that fall off, but that does not mean immunity is gone. It only means the antibody levels are waning. The body won't make more antibotides when there is no exposure to a virus. But, the good news is, cellular memory is still very likely present and should your pet ever be exposed to this virus again, BOOM, the antibody production factory fires up and the titer rises once again, and rather quickly at that.

So, it’d be a mistake to equate a titer that’s fallen with a lack of protection, and a greater one to think you need more vaccinations to re-establish protection. Immunity is still there, quietly, watchfully alert.

VacciCheck does NOT test for Leptospirosis, only distemper, hepatitis and parvo virus in dogs (different diseases are tested for in cats).

The nature of Leptospirosis means that annual vaccinations are required and there is not a titre test available that can give reliable results for long term immunity
(as VacciCheck can for DHP).

For more information contact Vacci Check HERE