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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 Border Collie we have compiled 3 mandatory and 11 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 Border Collie receives a B grade because it has an average health burden that is well-manageable through selective breeding. Key areas of concern include hip dysplasia (HD), which is monitored through mandatory health tests, as well as risks associated with the M-locus (merle factor), which can lead to severe defects if pairings are performed improperly. Buyers who consistently check the test results of the parents when purchasing a puppy will find a very robust companion.
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 Border Collie we track 3 mandatory tests plus 11 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 11 additional clinically recommended screenings that reduce risk in this breed.
In addition to mandatory tests:
Canine cyclic hematopoiesis(GCS)
Andere
This is an inherited bone marrow disorder where the body's production of blood cells, particularly infection-fighting white blood cells, drops drastically at regular intervals. This cyclic drop temporarily leaves the dog's immune system highly vulnerable to infections. The condition is caused by a genetic mutation affecting how stem cells in the bone marrow mature.
DNA · Passing: CARRIER
Dental hypomineralization(DH)
Andere
This is an inherited dental disorder where the outer protective layer of the teeth, known as enamel, does not mineralize properly during development. Because the enamel remains soft and thin, the teeth lack their normal protective shield and are highly prone to damage. This genetic condition is inherited in an autosomal-recessive manner, meaning a puppy must inherit the mutated gene from both parents to be affected.
Physisch · Passing: Clear or Carrier
Microphthalmia
Augen
Microphthalmia is a congenital developmental disorder of the visual system where one or both of a dog's eyeballs are abnormally small. This structural defect occurs during embryonic development and is often accompanied by other eye abnormalities, such as cataracts, which are cloudy areas in the lens of the eye. Because the eyeball itself is underdeveloped, the surrounding eyelids may also appear droopy or misaligned.
Passing: CLEAR
Progressive Retinal Atrophy (PRA)(PRA)
Augen
Progressive Retinal Atrophy (PRA) is an inherited eye disease that affects the retina, which is the light-sensitive layer of tissue at the back of the eye. In this condition, the specialized cells responsible for detecting light, known as photoreceptors, gradually degenerate and die. Because these cells cannot recover or be replaced, the disease slowly but inevitably leads to complete blindness.
Passing: CARRIER
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
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
Pannus (Chronic Superficial Keratitis)(CSK)
Augen und Sehvermögen
Pannus, or chronic superficial keratitis, is an immune-mediated disease affecting the cornea, which is the clear outer surface of the eye. In this condition, the dog's immune system mistakenly attacks the cornea, causing blood vessels and dark pigment to grow across it. This process is worsened by exposure to ultraviolet (UV) light and can eventually block the dog's vision.
Augen · Passing: CLEAR
Hip dysplasia(HD)
Bewegungsapparat
Hip dysplasia is an inherited skeletal disorder where the ball and socket of the hip joint do not fit together properly. Instead of sliding smoothly, the bones rub and grind against each other, wearing down the protective cartilage. Over time, this chronic friction causes joint instability, painful inflammation, and progressive arthritis, which is the gradual wear and tear of the joint.
Roentgen · Passing: B or better
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
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 · Passing: CLEAR
Adult-onset deafness(AOD)
Ohren und Gehör
This condition is a progressive form of hearing loss that affects the auditory system, specifically the sensory cells within the inner ear. Over time, these specialized cells degenerate and lose their ability to transmit sound signals to the brain. Because it is an inherited disorder, this deterioration occurs naturally as the dog matures, even though the outer ear looks completely healthy.
DNA · 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 — Merle coat pattern
Both parents must be CARRIER 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.
3 tests are currently mandatory under the relevant breed-club regulations. The most common are Collie eye anomaly (CEA) (CEA), Merle coat pattern (M), MDR1 gene mutation (drug sensitivity) (MDR1). 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