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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 Toy Manchester Terrier we have compiled 13 mandatory and 5 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 Toy Manchester Terrier is an agile and generally robust companion, but the breed does carry specific health risks such as von Willebrand disease (a blood clotting disorder) and Primary Lens Luxation (PLL). Fortunately, both conditions can be effectively managed through genetic testing of the parent dogs. Additionally, the kneecaps should be checked by a veterinarian for patellar luxation to prevent future lameness.
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 Toy Manchester Terrier we track 13 mandatory tests plus 5 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 5 additional clinically recommended screenings that reduce risk in this breed.
In addition to mandatory tests:
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: 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 or Carrier
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
Juvenile Dilated Cardiomyopathy(JDCM)
Herz
This is a severe, inherited heart disease where the heart muscle becomes abnormally enlarged and weakened, preventing it from pumping blood effectively. It is an autosomal-recessive condition that primarily affects young Portuguese Water Dogs and Toy Manchester Terriers. In Toy Manchester Terriers, the disease is linked to a mutation in a cardiac potassium channel, which is a protein essential for maintaining a normal heart rhythm.
Passing: CARRIER
Hypothyroidism
Hormonelles und Stoffwechsel
Hypothyroidism is an endocrine disorder where the thyroid gland, located in the neck, fails to produce enough thyroid hormones. These hormones are essential for regulating the body's metabolic rate, which is the speed at which cells convert nutrients into energy. When hormone levels are too low, the dog's entire metabolism slows down, affecting multiple organ systems.
Koerperfluessigkeiten · 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 0 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.
13 tests are currently mandatory under the relevant breed-club regulations. The most common are DNA-Identitätsnachweis, Ocular anomalies, Cone-rod dystrophy 3 (crd3) (crd3). 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