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Health Testing Guide
Which tests are mandatory, how to spot responsible breeders — and what it costs when things go wrong.
For the English Toy Terrier (Black and Tan) we've compiled 9 core tests (1 of them required by Klub für Terrier e.V.) and 1 additionally recommended test, drawn from breed-club regulations, the University of PEI (CIDD), and OMIA — weighted by severity and heritability.
View verified breedersWhat this grade means
In the English Toy Terrier (Black and Tan), there are breed-typical risks for eye diseases such as primary open-angle glaucoma, cataract, and progressive retinal atrophy, as well as for patellar luxation (PL) and anatomical abnormalities such as open fontanelles (cranial lacunae). The Klub für Terrier e.V. prescribes an examination for patellar luxation (PL), under which only values of PL 0–1 are permitted. Furthermore, a responsible breeder has the parent animals examined for eye diseases and also screens for Von Willebrand disease type I, where carriers may only be mated with clear partners. Therefore, ask to be presented with the official PL report as well as written proof of eye clearance and cranial health.
Every breed is susceptible to certain inherited conditions. Just like humans, dogs inherit predispositions from their parents. Responsible breeders screen their breeding dogs for these conditions and make informed mating decisions to reduce the risk passed on to puppies.
No — but it's the strongest tool we have. Diet, exercise, environment, and genetics all contribute to whether a dog develops a condition. When breeders use the right tests to identify risk in potential parents, the likelihood of many conditions appearing in the puppies drops significantly.
There's no one-size-fits-all here. The core standard for the English Toy Terrier (Black and Tan) covers 9 tests, 1 of them required by Klub für Terrier e.V., plus 1 additional recommended test. The specific tests and passing thresholds are detailed further below.
Keep in mind
Reliable screening tests still don't exist for many hereditary conditions, and tests for complex polygenic conditions don't always predict severity in the puppies. Even so, they're a powerful tool of responsible breeding.
There are two main types of health tests:
Screen the dog's DNA for known disease-causing mutations. Can be performed from puppyhood and give a binary result (clear / carrier / affected).
Clinical and imaging exams like X-ray, ultrasound, or ophthalmoscopy. They show how a predisposition actually manifests — usually only conclusive after 12–18 months.
We group breeding programs into three levels based on testing depth. Ask your breeder directly which level they meet.
A breeder at the Great level meets the Good level and performs 1 additional clinically recommended screening that reduces risk in this breed.
In addition to Good:
Von Willebrand disease type I(vWD1)
Stoffwechsel
Von Willebrand Disease Type I is an inherited bleeding disorder that affects the blood's ability to clot properly. It is caused by a deficiency in von Willebrand factor, a specific protein that helps blood platelets stick together to plug damaged blood vessels. Because this is an autosomal-dominant condition, a dog only needs to inherit one copy of the mutated gene to potentially show symptoms.
Passing: clear or carrier
These levels are a comparison framework, not an official certification. They help compare breeding programs at a glance.
A complete checklist with every core-standard and additionally recommended test, plus identity and rearing questions — take it with you.
Open the full checklistFor breeders
Machine-readable mating rules, minimum ages, scoring schemes, and what's required for HonestDog verification — as a printable guide.
Example rule — Ectropion / Entropion
Both parents must be clear or better.
We take mandatory tests from official breed regulations, build the recommended health standard from veterinary databases — and cross-check every uploaded certificate against the dog's profile using AI.
L1 = core standard: the club's required tests where its rules set them, otherwise the recommended health standard for the breed. L2 = additionally recommended or clinically indicated. L3 = lower prevalence. Every assignment carries a source and confidence rating.
VDH breeding regulations, CIDD (University of PEI), OMIA (University of Sydney), curated veterinary input.
Uploaded certificates are read by AI and checked for date, result, and consistency with the dog's profile — our team reviews anything inconclusive.
These hereditary conditions are currently classified as most relevant for the English Toy Terrier (Black and Tan): Apple head, Ectropion / Entropion, Cataract (HC), Primary Open-Angle Glaucoma (POAG), Progressive Retinal Atrophy (PRA) (PRA), Retinal Dysplasia (RD), Cranioschisis, Patellar Luxation (PL), Juvenile Dilated Cardiomyopathy (JDCM). The risk for a puppy depends primarily on whether both parents have been tested for these conditions and whether the results fall within breed-specific requirements.
Self-check
Answer 6 quick questions about your everyday life and see how well the English Toy Terrier (Black and Tan) fits you — including an honest cost estimate per month, per year, and across the dog's lifetime.
See breeders who have already uploaded their health test results for verification.
View verified breeders