As a dog breeder and someone who’s walked dozens of puppy owners through vaccination decisions, I want to talk about something that not enough people are doing — titer testing for parvovirus and distemper after your puppy’s last core vaccination at around 16 weeks of age.
Most puppies get a series of shots designed to protect them from some of the deadliest viral diseases we see in dogs: canine parvovirus and canine distemper. But here’s the key thing — just because the shots have been administered doesn’t guarantee that your puppy has developed actual immunity. That’s where titer testing comes in. (Read more: DVM360)
What Is a Titer Test — And Why It Matters
A titer test is a simple blood test that measures how much antibody your dog has against specific viruses. In plain language: it tells you whether your puppy’s immune system has actually responded to the vaccines. A titer is a quantitative number (not just “yes/no”) showing how strongly your pup’s blood can neutralize the virus in a lab test. (Read more: UW-Madison Vet School)
Why having a titer is important?
- Vaccines are not perfect for every individual puppy. Maternal antibodies — antibodies passed from mom through milk — can neutralize the vaccine before it even works, leaving your puppy unprotected even after multiple shots. (DVM360)
- A titer lets you know if your puppy is protected — rather than assuming protection. (UW-Madison Vet School)
And trust me, as someone who’s helped many passionate dog owners think through these choices: a little information goes a long way in peace of mind.
Why Test After The Final Puppy Shot
Veterinary science and vaccination guidelines are very clear — the best time to check immunity is at least two weeks after your puppy’s final core vaccine (usually around 16–18 weeks). That’s because by that time, maternal antibodies have usually faded, and your pup should be capable of mounting their own immune response. (UW-Madison Vet School)
Testing too early can give a false sense of security because maternal antibodies might still be present and might interfere with both vaccination and the test itself. Waiting the full period gives a much more accurate picture of your pup’s actual immunity. (UW-Madison Vet School)
The CAVIDS Lab at the University of Wisconsin-Madison
One of the most trusted places to get accurate canine titer testing is the Companion Animal Vaccine and Immuno Diagnostic Service (CAVIDS) Laboratory at the University of Wisconsin-Madison School of Veterinary Medicine. They have decades of experience testing for antibody levels against canine distemper virus (CDV), canine parvovirus (CPV-2), and canine adenovirus — all core vaccine viruses. Visit the UW-Madison Vet School CAVIDS website for more information.
Here’s what’s great about CAVIDS:
- You can submit samples without a pre-existing account.
- They provide quantitative, functional titers — not just yes/no answers.
- They test using gold-standard lab methods, so you’re getting real insight into your dog’s immunity.
Their lab offers a parvo/distemper panel, and you can send in your puppy’s serum to be tested. You’ll get back a number and interpretation that tells you whether your pup has the levels of antibody associated with protection.
You can start exploring what they do here:
https://www.vetmed.wisc.edu/lab/cavids/ — CAVIDS Titer Testing Laboratory (UW-Madison Vet School)
If the Titer Shows Low or No Antibodies
This is exactly why you test.
If the titer comes back below the protective threshold, it means your puppy hasn’t developed enough measurable antibody yet — even after all those shots. At that point, a booster vaccine is not only reasonable — it’s a smart, evidence-based approach to protect your dog before he’s exposed to real disease.
Then you can repeat the titer 2–4 weeks later to confirm immunity — and that’s a level of precision you don’t get by blindly revaccinating at fixed intervals.
Bottom Line
Here’s my honest take:
Getting a parvo/distemper titer after your puppy’s final 16-week vaccination is one of the most informed, responsible things you can do as a dog owner. It lets you know your puppy is protected, avoids unnecessary boosters, and gives you peace of mind during those first months when your pup’s immune system is still finding its footing.
Vaccines save lives. But testing lets you understand how those vaccines are working for your dog. And for something as serious as parvo or distemper — diseases that can be deadly even in older dogs — that knowledge is priceless.
