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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 King Charles Spaniel we have compiled 5 mandatory and 4 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 King Charles Spaniel receives a grade of D because the breed suffers from significant anatomical and health-related challenges. In particular, breathing difficulties due to extreme brachycephaly and a very high rate of cesarean sections during birth place a heavy burden on the breed. Additionally, patellar luxation is a common issue affecting the musculoskeletal system, which prospective puppy buyers should critically inquire about beforehand.
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 King Charles Spaniel we track 5 mandatory tests plus 4 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 4 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
Retinal Dysplasia(RD)
Augen
Retinal dysplasia is a congenital condition affecting the eyes, where the retina (the light-sensitive tissue at the back of the eye) does not develop properly during growth in the womb. This abnormal development leads to structural defects like folds or gaps in the retinal layers. Because the retina is responsible for sending visual signals to the brain, these imperfections can impair normal vision.
Augen · Passing: CLEAR
Cataract(HC)
Augen und Sehvermögen
A cataract is a progressive clouding of the lens inside the dog's eye, which is the clear structure that focuses light onto the retina at the back of the eye. When the lens becomes cloudy or opaque, it blocks light from entering, gradually impairing the dog's vision. If left untreated, this condition can eventually lead to complete blindness in the affected eye.
Augen · Passing: CLEAR
Episodic Falling(EF)
Nervensystem
Episodic Falling is an inherited neurological disorder where the nervous system fails to properly regulate muscle tone. When triggered by excitement, stress, or exercise, the muscles in the limbs temporarily tighten and cramp. This causes the dog to lose control of its movement, although they remain fully conscious throughout the episode.
DNA · 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 — Patellar Luxation
Both parents must be Grad 0 oder 1 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.
5 tests are currently mandatory under the relevant breed-club regulations. The most common are Cesarean section, Brachycephalic obstructive airway syndrome (BOAS) (BOAS), Patellar Luxation (PL). 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