To titer or not to titer

In this episode of Vet Watch, Noga Shiller, DVM, veterinary medical advisor at Biogal Labs, joins host Christopher Lee, DVM, MPH, DACVPM, DACVM (Parasitology), to unpack how titer testing fits into everyday practice, from the roughly 20-week post-vaccination check in puppies, to identifying the rare non-responder patient, to managing senior and immunosuppressed dogs for whom an unnecessary booster carries added risk.

Shiller emphasized that titers are not a workaround for vaccination but a way to time it appropriately, noting that titer testing is not a substitute for vaccinations. She also addressed the practical side for clinics considering in-house testing: turnaround time, validation against laboratory gold standards, the role titers can play in building trust with vaccine-hesitant clients, and more.

Below is a partial transcript, edited lightly for clarity.

Christopher Lee, DVM, MPH, DACVPM, DACVM (Parasitology): So, what do titers tell us? How can we use them?

Noga Schiller, DVM: All right. So that's a great question because titer testing is not going to work for every type of virus or bacteria that we vaccinate for. So, where titer testing is really going to help is for 4 particular core viruses. So in dogs, it's for our distemper virus, adenovirus, and parvovirus, and then for cats, it's for our panleukopenia virus.

Now the reason that titer testing is really good for these 4 viruses. So there are 2 main reasons. The first one is the pathogens themselves. So for these particular viruses, our antibodies, our IgG antibodies, have an extremely important role in protection against disease. So they're going to be the first line of defense, and they're going to block the viruses from even from causing infection. They're going to lead to what is called sterilizing immunity.

The other reason these are 4 good viruses to titer test for is that the vaccine we give is a modified live vaccine, and these types of vaccines do lead, in most cases, to a very long duration of immunity. So in most dogs and in most cats, we're going to have years of protection just from one vaccination done at the correct time. This is different for other types of vaccines.

So, for example, for Leptospira vaccine, titer testing isn't really going to work because the Leptospira vaccine does not lead to a very long duration of immunity, these are vaccines that we are going to need to repeat once a year. Another example is the Bordetella vaccine. So the Bordetella vaccine…has a very strong component of local immunity, which is our IgA antibodies, and therefore titer testing for IgG antibodies is not going to be strongly correlated with protection.

Want to hear more of this conversation? Check out the full episode at the top of this page!