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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 Parson Russell Terrier we have compiled 8 mandatory and 6 recommended health tests, drawn from breed-club regulations, the University of PEI (CIDD), and OMIA — weighted by severity and heritability.
What this grade means
The Parson Russell Terrier is fundamentally a very robust working dog, but it carries genetic risks for eye conditions such as Progressive Retinal Atrophy (PRA) and cataracts. Patellar luxation, an instability of the kneecap, is also a known issue for this breed size. However, these risks can be well managed through mandatory health tests when purchasing a puppy, which is why the breed generally enjoys solid 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. For the Parson Russell Terrier we track 8 mandatory tests plus 6 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 are not always predictive of severity in the puppies. Even so, they're a powerful tool used by every responsible breeder.
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 6 additional clinically recommended screenings that reduce risk in this breed.
In addition to mandatory tests:
Lens luxation(PLL)
Augen und Sehvermögen
Lens luxation is an inherited eye disorder where the lens slips out of its normal position because the supporting fibers holding it in place weaken or break. When the lens shifts, it can block the natural drainage of fluid within the eye. This blockage causes a rapid, painful buildup of pressure called glaucoma, which can lead to permanent blindness if left untreated.
Augen · Passing: Clear or Carrier
Congenital Myasthenic Syndrome(CMS)
Bewegungsapparat
Congenital Myasthenic Syndrome (CMS) is an inherited genetic disorder that disrupts the communication between nerves and muscles. This breakdown in the neuromuscular system prevents signals from reaching the muscles properly, leading to rapid muscle fatigue and weakness. Unlike some other muscle-weakness disorders, this is a congenital condition present from birth and is not caused by an autoimmune system malfunction.
DNA
Ichthyosis(ICT)
Haut und Fell
Ichthyosis is an inherited skin disorder where the outer layer of the skin, the epidermis, does not develop or shed properly. This defect in keratinization—the process of forming a protective outer skin barrier—leads to a buildup of dry, thick, and scaly skin. Because this barrier is compromised, the dog's body is more vulnerable to secondary infections.
Cerebellar abiotrophy(CA)
Nervensystem
Cerebellar abiotrophy is an inherited neurological disorder affecting the brain, specifically the cerebellum, which regulates balance and movement coordination. In affected dogs, the nerve cells in this region prematurely degenerate and die off. This progressive cell loss disrupts the brain's ability to control smooth physical movements.
DNA
Globoid cell leukodystrophy (galactocerebrosidosis)(GCL)
Nervensystem
Globoid cell leukodystrophy is an inherited metabolic disorder affecting the nervous system, caused by a deficiency in an essential enzyme. This deficiency leads to the buildup of harmful substances that destroy myelin, which is the protective sheath surrounding nerve fibers in the brain and spinal cord. Without this protective covering, the nerves cannot transmit signals properly, resulting in progressive neurological decline.
DNA
Urolithiasis
Nieren
Urolithiasis is the formation of mineral stones within the urinary tract, which includes the kidneys, bladder, and connecting tubes. These solid crystal clusters develop when minerals in the urine clump together instead of dissolving. Over time, these stones can irritate the sensitive lining of the urinary system or completely block the flow of urine.
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 — Ectropion / Entropion
Both parents must be CLEAR or better.
We compile mandatory tests from official breed regulations and veterinary databases — and check every uploaded certificate for authenticity.
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 AI-extracted and reviewed by our team for authenticity, date, and result.
8 tests are currently mandatory under the relevant breed-club regulations. The most common are Apple head, Ectropion / Entropion, Progressive Retinal Atrophy (PRA) (PRA). Every test must be completed before mating, and the result must fall within the threshold defined by the regulation.
See breeders who have already uploaded their mandatory tests for verification.
View verified breeders