The health tests to ask a breeder for
3 min read · Updated
The single most useful thing a buyer can do is ask for test results and then actually look at them. This matters because of one piece of genetics: for a recessive disease, a carrier is entirely healthy and indistinguishable from a clear animal. You cannot see it, the breeder cannot see it, and no amount of the puppies are all really healthy substitutes for a test that costs less than a bag of food.
Three different kinds of test
A DNA test looks at the gene itself and returns clear, carrier or affected. It is definitive, it can be done at any age, and it never needs repeating. Most of the named diseases in the breed profiles on this site are in this category.
A screening scheme measures a physical structure at a point in time. Hip and elbow scoring uses radiographs read by a panel; eye examinations look for changes that develop with age and are repeated annually; cardiac schemes use auscultation or ultrasound. These describe the animal now rather than its genes, which is why they are repeated and why a breeder should have current certificates.
A BAER test measures hearing electrically, and is the only way to know whether an animal is deaf in one ear. It matters in white and merle-patterned animals, where one-sided deafness is easy to miss entirely.
Dogs
Hip and elbow scores under a recognised scheme — BVA in Britain and Ireland, OFA in the United States, FCI across much of Europe. Hip scores are numbers rather than a pass or fail, so compare them against the current breed median, which the scheme publishes.
Annual eye examination for breeds where it applies, plus DNA tests for the specific conditions in the breed. The common ones include progressive retinal atrophy in dozens of breeds, degenerative myelopathy, MDR1 drug sensitivity throughout the collie lineage, von Willebrand disease, exercise-induced collapse in retrievers and spaniels, and a long list of breed-specific ones — copper toxicosis in Bedlington terriers, JLPP in Black Russian terriers, congenital night blindness in Briards, CLAD in Irish red and white setters, footpad hyperkeratosis in Irish terriers.
Heart schemes matter in Cavalier King Charles spaniels and Dobermanns particularly. Respiratory function grading applies to the flat-faced breeds.
Cats
Hypertrophic cardiomyopathy is the most important condition in pedigree cats and, for most breeds, it is screened by echocardiogram rather than DNA. Maine Coons and Ragdolls have DNA tests for specific mutations, but a clear DNA result does not mean a cat will not develop HCM by another route — scanning is what tells you. Sphynx, Bengal and British breeds should be scanned.
Polycystic kidney disease has a definitive DNA test and travels with Persian ancestry, which means Exotics, British Longhairs, Selkirk Rex, Burmilla, Napoleon and anything else outcrossed to Persians.
Other DNA tests worth naming: progressive retinal atrophy across several breeds, pyruvate kinase deficiency in Abyssinian and Somali lines, GM1 and GM2 gangliosidosis in the Korat, GM2 in the Japanese Chin, hypokalaemia in Burmese-derived breeds, and Fanconi-type conditions where they apply.
Horses
The Quarter Horse five-panel test covers HYPP, PSSM1, GBED, HERDA and malignant hyperthermia in one go, and results on registered horses are often publicly visible. It applies to Paints, Appaloosas and Aztecas through shared bloodlines.
Overo lethal white syndrome in Paints and any frame overo horse. Two frame carriers bred together produce a foal that is born white, appears normal and dies within days.
Arabians and Arabian crosses: SCID, cerebellar abiotrophy and lavender foal syndrome.
Akhal-Tekes: Naked Foal Syndrome. Belgians and other heavy drafts: junctional epidermolysis bullosa. PSSM1 across the draft breeds generally.
How to read the answers
A clear-to-carrier pairing is fine and produces no affected animals — carriers are healthy, and excluding every carrier from a small gene pool does more harm than the disease. What should never happen is carrier bred to carrier.
Clear by parentage is legitimate but depends entirely on the parents having been tested and the parentage being correct. Prefer a directly tested animal where the disease is serious.
Ask to see the certificates rather than accepting a summary, and check the animal's registered name and microchip on them.
The answers that should end the conversation: vet checked instead of tested — a vet check is a physical examination and detects none of this. We have never had a problem in our lines — the whole point of a recessive is that you would not know. Refusing to show paperwork. And testing for the easy cheap conditions while being vague about the expensive structural ones.