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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 Great Pyrenees we have compiled 4 mandatory and 7 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 Pyrenäen-Berghund receives a grade of C because, as a very large breed, it has typical vulnerabilities in its musculoskeletal system. Hip dysplasia (HD) and elbow dysplasia (ED) are well-known risks that must be monitored through mandatory health tests. Osteochondrodysplasia (OCD) also requires attention, which is why buyers should insist on seeing certified X-ray results for both parent dogs.
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 Great Pyrenees we track 4 mandatory tests plus 7 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 7 additional clinically recommended screenings that reduce risk in this breed.
In addition to mandatory tests:
Ectropion / Entropion
Augen
These are structural eyelid abnormalities affecting a dog's eyes. In cases of entropion, the eyelid rolls inward, causing the eyelashes or fur to rub painfully against the surface of the eyeball. In ectropion, the eyelid sags or rolls outward, leaving the sensitive inner lining of the eye exposed and unprotected.
Passing: CLEAR
Cervical vertebral compressive myelopathy(CVCM)
Bewegungsapparat
Cervical vertebral compressive myelopathy, commonly known as Wobbler syndrome, is a condition affecting the spine where the spinal cord in the neck becomes pinched. This compression is caused by malformed neck vertebrae or slipping discs between the bones. Over time, the constant pressure damages the nerve pathways that carry signals from the brain to the limbs.
Roentgen · Passing: A
Chondrodysplasia, SLC13A1-related
Bewegungsapparat
This is an inherited form of dwarfism affecting the skeletal system, specifically bone and cartilage development. It is caused by a genetic mutation that leads to a deficiency in sulfate, a compound crucial for healthy bone growth. Without enough sulfate, the dog's skeleton cannot develop to its normal size and structure.
Passing: CARRIER
Platelet dysfunction (thrombocytopathia, Basset hound thrombopathia)(BHT)
Herz und Kreislauf
This is an inherited blood clotting disorder caused by a genetic mutation in the RASGRP2 gene, which affects how platelets (the blood cells responsible for stopping bleeding) function. Even though the dog has a normal number of platelets, these cells cannot clump together properly to form clots. This impairs the circulatory system's ability to heal wounds and control bleeding.
DNA · Passing: CARRIER
Tricuspid valve dysplasia(TVD)
Herz und Kreislauf
Tricuspid valve dysplasia is a congenital heart defect where the tricuspid valve, located on the right side of the heart, does not develop normally. This valve normally acts as a one-way gate, but its malformation prevents it from closing properly. As a result, blood leaks backward into the right atrium instead of flowing forward to the lungs, forcing the heart to work much harder.
Ultraschall · Passing: NORMAL
Congenital deafness(CHSD)
Nervensystem
Congenital deafness is a hereditary hearing loss present from birth that affects the inner ear's sensory cells, preventing sound signals from reaching the brain. It is often linked to specific genetic variants, such as those associated with certain coat patterns like merle or piebald, or breed-specific conditions like Early Onset Adult Deafness (EOAD). This genetic defect causes the vital blood supply to the inner ear to fail, leading to the permanent degeneration of the hearing nerve cells.
Physisch · Passing: BILATERAL_HEARING
Bleeding disorder
Stoffwechsel
A bleeding disorder is a malfunction of the circulatory system where the blood cannot clot properly due to missing or defective clotting factors or platelets, which are the cells responsible for plugging damaged blood vessels. This impairment prevents the body from effectively sealing wounds, leading to prolonged internal or external bleeding.
Passing: 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 — Ocular anomalies
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.
4 tests are currently mandatory under the relevant breed-club regulations. The most common are Ocular anomalies, Elbow Dysplasia (ED), Hip dysplasia (HD). 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