Health Testing Guide
Which tests are mandatory, how to spot responsible breeders — and what it costs when things go wrong.
For the Toy Fox Terrier we've compiled 4 mandatory and 2 recommended health tests, drawn from breed-club regulations, the University of PEI (CIDD), and OMIA — weighted by severity and heritability.
View verified breedersWhat this grade means
The Toy Fox Terrier receives a grade of B. Although the breed carries predispositions to severe conditions such as Primary Lens Luxation (PLL), which can lead to blindness, and Spinocerebellar Ataxia (SCA), these and other risks, such as von Willebrand's Disease (vWD), can be reliably ruled out in advance via simple DNA tests. Consequently, the breed is in good health when responsibly bred.
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. For the Toy Fox Terrier we track 4 mandatory tests plus 2 additional recommended ones. 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 performs all mandatory tests plus 2 additional clinically recommended screenings that reduce risk in this breed.
In addition to mandatory tests:
Patellar Luxation(PL)
Bewegungsapparat
Patellar luxation, also known as a luxating patella, is a physical condition affecting the knee joint where the kneecap slips out of its normal groove. This misalignment interferes with the mechanical movement of the hind leg and can cause the joint to lock. Over time, this abnormal friction can lead to painful joint wear and tear, known as osteoarthritis.
Physical examination · Passing: PL 0
Degenerative Myelopathy(DM)
Nervensystem
Degenerative Myelopathy is a progressive disease of the spinal cord where the protective sheath around the nerves slowly breaks down. This deterioration disrupts the vital communication signals between the brain and the muscles of the hind limbs. Over time, this lack of signal transmission leads to a complete loss of muscle control in the back legs.
DNA test · 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 mandatory and 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 — Lens luxation
Both parents must be clear or carrier or better.
We compile mandatory tests from official breed regulations and veterinary databases — and cross-check every uploaded certificate against the dog's profile using AI.
L1 = mandatory under breed-club regulations. L2 = 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.
The Toy Fox Terrier is not currently listed in our extreme-breeding overview. That does not mean it is free of hereditary disease: which ones are typical, and which tests the parents should have, is on this page.
Self-check
Answer 6 quick questions about your everyday life and see how well the Toy Fox Terrier fits you — including an honest cost estimate per month, per year, and across the dog's lifetime.
See breeders who have already uploaded their mandatory tests for verification.
View verified breeders