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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 Yorkshire Terrier we have compiled 4 mandatory and 10 recommended health tests, drawn from breed-club regulations, the University of PEI (CIDD), and OMIA — weighted by severity and heritability.
What this grade means
While the Yorkshire Terrier is often long-lived, it struggles with typical toy breed issues such as patellar luxation and tracheal collapse. Since there are no mandatory genetic tests for these conditions or for the dangerous portosystemic shunt, breeding selection is often insufficiently controlled. Buyers should be aware that joints and airways remain vulnerable without strict selection of the parent animals.
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 Yorkshire Terrier we track 4 mandatory tests plus 10 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 10 additional clinically recommended screenings that reduce risk in this breed.
In addition to mandatory tests:
Tracheal collapse(TC)
Atmung
Tracheal collapse is a progressive respiratory condition where the C-shaped cartilage rings that keep the windpipe (trachea) open begin to weaken and flatten. As these supportive rings lose their rigidity, the airway narrows, making it difficult for air to pass smoothly into the lungs. This mechanical failure of the respiratory tract leads to chronic irritation and breathing difficulties.
Roentgen · Passing: A
Keratoconjunctivitis sicca (KCS) - "dry eye"(KCS)
Augen
Keratoconjunctivitis sicca (KCS), commonly known as dry eye, is a chronic disease of the ocular system where the tear glands fail to produce enough natural tears. Without this protective moisture, the cornea (the clear surface of the eye) and surrounding tissues become dry, inflamed, and highly susceptible to painful damage.
Augen · 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
Legg-Calvé-Perthes disease(LCPD)
Bewegungsapparat
Legg-Calvé-Perthes disease is a serious orthopedic condition affecting the hip joint, primarily in small breed dogs. It occurs when the blood supply to the head of the thigh bone, known as the femur, is spontaneously disrupted. Without blood, this bone tissue dies and collapses, leading to severe joint inflammation and pain.
Roentgen · Passing: A
Patent ductus arteriosus (PDA)(PDA)
Herz
Patent ductus arteriosus is a congenital heart defect where a normal fetal blood vessel connecting the aorta and the pulmonary artery fails to close shortly after birth. This failure allows blood to continuously recirculate through the lungs instead of flowing to the rest of the body, putting severe, permanent strain on the heart muscle. Over time, this volume overload causes the left side of the heart to enlarge and weaken.
Ultraschall · Passing: NORMAL
Hyperadrenocorticism (Cushing's syndrome)(HAC)
Hormonelles und Stoffwechsel
Cushing's syndrome is a hormonal disorder affecting the endocrine system, where the adrenal glands chronically produce too much of the stress hormone cortisol. This overproduction disrupts the dog's normal metabolism, fluid balance, and immune system function. It is typically caused by a benign tumor in either the pituitary gland or the adrenal glands themselves.
Koerperfluessigkeiten · Passing: CLEAR
Hydrocephalus
Nervensystem
Hydrocephalus is a neurological condition affecting the brain and nervous system, commonly referred to as water on the brain. It occurs when cerebrospinal fluid, the natural protective liquid surrounding the brain, builds up abnormally inside the brain's cavities, known as ventricles. This accumulation creates harmful pressure on the surrounding brain tissue, which can impair normal brain function.
Roentgen · Passing: A
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.
Passing: CLEAR
Portosystemic hepatic encephalopathy(PSS)
Stoffwechsel
This is a neurological condition caused by liver dysfunction, typically occurring when abnormal blood vessels bypass the liver. Because the liver cannot filter toxins from the bloodstream, these harmful substances build up and directly affect the brain. This lack of proper filtration leads to central nervous system dysfunction.
Passing: NORMAL
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 1 or better 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 DNA-Identitätsnachweis, Zahn- und Bissbewertung, 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