Loading health guide
Health Testing Guide
Which tests are mandatory, how to spot responsible breeders — and what it costs when things go wrong.
For the American Collie we have compiled 7 mandatory and 2 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 American Collie receives a grade of C because the breed carries an above-average number of genetic risks. The well-known MDR1 defect (drug sensitivity) and Collie Eye Anomaly (CEA) are breed-specific issues that are, however, well-managed through strict mandatory health tests. Buyers should also be aware of the skin condition dermatomyositis (DMS) and insist on seeing complete, gap-free test results for both parents.
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 American Collie we track 7 mandatory tests plus 2 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 2 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
Merle coat pattern(M)
Haut und Fell
The merle coat pattern is caused by an autosomal-dominant mutation in the PMEL gene, which affects pigment-producing cells in the skin, eyes, and inner ears. When a dog inherits two copies of this gene, a condition known as double merle, it disrupts the normal development of these sensory organs. This genetic defect can lead to severe structural abnormalities in both the auditory and visual systems.
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 — Collie eye anomaly (CEA)
Both parents must be Clear or 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.
7 tests are currently mandatory under the relevant breed-club regulations. The most common are Inflammatory Pulmonary Disease (IPD), Collie eye anomaly (CEA) (CEA), Progressive Retinal Atrophy, Rod-Cone Dysplasia 2 (PRA-rcd2). 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