Clinical vs DNA Pre-Breeding Testing: What These Actually Tell You

Quick answer: Health testing comes in two flavors.

• Clinical tests check the dog itself, like hip x-rays and heart exams.

• DNA tests check the dog’s genes.

DNA tests can completely rule out some specific diseases when both parents test clear. But for most of the common stuff we worry about, like hip dysplasia, slipping kneecaps, and most heart defects, there’s no DNA test that clears a dog. For those, testing lowers the risk. It doesn’t get rid of it.

Most of us know to run health clearances before breeding. The fuzzier part is what those clearances actually prove, and where they fall short.

What does a clinical health test actually tell you?

Clinical tests check the dog in front of you, on the day of the exam. Hip and elbow x-rays, heart exams, knee checks, eye exams, hearing tests, thyroid panels. All of them are snapshots of how the dog looks and works right now.

A clean heart exam means the cardiologist didn’t hear or see a problem on the day they looked. It doesn’t tell you whether the dog carries the genes for a heart defect that could show up in the puppies.

A dog with passing hips can still throw dysplastic puppies, because hip health is created by many genes working together (“polygenic”) and shaped by environment. A parent can carry the genes for a condition without ever showing the condition themselves.

That’s the part that trips a lot of breeders up. A clean clearance is meaningful. It’s not the same as a genetic guarantee.

What does a DNA test actually tell you?

DNA tests look at specific areas in the dog’s genes. For diseases caused by one specific gene (“Mendelian” inheritance), the tests are powerful.

Things like progressive retinal atrophy (PRA), degenerative myelopathy (DM), and dozens of others can be predicted with very high confidence based on what the parents carry.

When both parents test clear, the puppies are clear for that specific disease. Period.

But DNA testing has its own limits. We can only test for what scientists have figured out.

Diseases like hip dysplasia, most heart problems, and many cancers don’t have a single DNA test that clears a dog. And the test panels keep growing, which means a dog you cleared five years ago might carry something we now know how to test for.

How do the two types work together?

They cover different ground.

• Clinical tests catch problems you can see in the dog right now.

• DNA tests catch some problems hiding in the genes that won’t show up unless paired with another carrier.

Together they give you a fuller picture, but the picture is never complete.

A dog with passing hips and a clear DM result is in good shape on those specific things. That same dog could carry something we don’t know how to test for yet, or could throw a problem that comes from many genes acting together.

What does this look like in practice?

There are many conditions with no DNA test available. Here are some common examples. For all of them, the clinical exam is the only screening tool you have.

Hip and elbow dysplasia

Both come from many genes plus environment. No DNA test clears a dog for either. The AKC's overview of hip dysplasia puts it plainly: x-ray screening through OFA or PennHIP is still the best tool we have, and dogs with normal hips can still produce affected puppies. The same logic applies to elbows, which are evaluated by x-ray as part of OFA's standard orthopedic workup. The Functional Breeding Podcast has a two-part interview with Dr. Mary Peaslee that goes deep on what hip testing can and can't tell you. (AKC, FBP with Dr. Peaslee, OFA Elbow Dysplasia)

Slipping kneecaps (patellar luxation)

Comes from many genes too. The vet screens for it by hand, checking how the kneecap sits in the joint. OFA recommends rechecking dogs over time, because some kneecap problems don’t show up until later in life.

A normal knee exam at a year old doesn’t promise the dog will stay that way, and it doesn’t tell you what the dog will pass on. (OFA Patellar Luxation)

Heart defects

Many of the heart conditions breeders watch for, including PDA (patent ductus arteriosus, a defect puppies are born with), subaortic stenosis, and mitral valve disease, have no DNA test that clears a dog. The condition often runs in families, but the only way to screen is to have the heart checked with a stethoscope, and a heart ultrasound ("echocardiogram") when something sounds off. On a recent Pure Dog Talk episode, vet and breeder Dr. Marty Greer makes the point that breeders have no choice but to lean on physical screening for these heart conditions. She also recommends that any heart ultrasound on breeding stock be done by a board-certified heart specialist, since the imaging is easy to read wrong. (Pure Dog Talk Ep 741, OFA Cardiac)

Eye disease

A lot of breeders assume their PRA DNA test covers eye health. It doesn't. PRA testing rules out the specific form of PRA the test is built for, but it doesn't catch the many other inherited eye problems that need a hands-on exam, including cataracts, certain retinal issues, and lid and eyelash problems. That's why a yearly eye exam by a board-certified veterinary eye specialist, recorded with OFA, is its own clearance, separate from any DNA test. (OFA Eye Certification Registry)

Inherited deafness

Common in breeds with certain coat color patterns. The screening tool is a BAER test, which measures how the dog's hearing nerves respond to sound. It picks up deafness in one or both ears, including the kind that's easy to miss in a dog that seems to hear fine at home. No DNA test currently clears a dog for the most common forms of inherited deafness, so the BAER exam is the screening. (OFA Congenital Deafness)

For all of these, the clinical work isn't optional. None of them give you a "DNA clear" stamp. The honest read is that you've done the screening, the dog looks normal, and you're making the best call you can with what you know.

Why is risk reduction the right way to think about it?

For most of the conditions breeders worry about, that’s what testing does. It lowers the odds of producing affected puppies without getting rid of them.

Single-gene diseases that testing exists for are the exception. When both parents test clear on a solid DNA test, that disease really is off the table for the litter.

But hip dysplasia, slipping kneecaps, most heart defects, and most of what shows up in long-term health surveys aren’t single-gene diseases. For those, testing lowers risk. It doesn’t eliminate it.

When breeders or buyers treat clearances as guarantees, two things happen. First, surprise diagnoses feel like a betrayal instead of a known possibility. Second, breeders stop paying attention to the risk that testing doesn’t catch, like what the relatives produced, how earlier litters from the same line have done, and the broader health record of the family.

A well-tested dog from a healthy line still carries some risk. Saying that out loud, with other breeders and with buyers, builds more trust than pretending otherwise.

One way to help: send buyers a version of this conversation written for them.

I have a companion post that explains testing limits in plain language for puppy families, which is useful if you want to set expectations early without having to explain it from scratch every time. (Link here: Why "Health Tested Parents" Doesn't Mean a Guaranteed Healthy Puppy)

What should breeders be doing beyond clearances?

A few things worth keeping in front of you:

Pay attention to the family, not just the dog.

Clearances on one dog don't tell you what that dog throws. A dog with perfect clearances can still come from a family that consistently produces a condition, and that pattern shows up in the relatives long before it shows up on the test results in front of you.

• What did the grandparents and littermates produce?

• Siblings and half-siblings tell you what the parents are passing on.

• Offspring from earlier breedings tell you what your dog is passing on.

The more data you can gather across the family, the better picture you have of what's actually moving through the line. This is where staying connected to other breeders matters. Public databases like OFA help, but a lot of the most useful information lives in conversations with the people who bred and own the relatives.

Use breeding value scores and open health databases when they exist for your breed. They pull data from the relatives and give you a fuller picture than a single test result.

Track what you produce. Following up with buyers over the years is one of the most underused tools breeders have for learning what their dogs really pass on.

Frequently asked questions

Can a dog with a normal heart exam still produce puppies with heart disease? Yes. The exam reflects what the cardiologist heard or saw on that day.

Most inherited heart conditions also come from many genes working together ("polygenic"), so a dog can carry the genes without ever showing the condition themselves.

A clean exam lowers the odds, but it doesn't rule out what the dog can pass on.

If both parents pass clinical and DNA testing, are the puppies guaranteed healthy? No. For specific single-gene diseases where both parents test clear, those diseases are ruled out for the puppies. But conditions that come from many genes, conditions that don’t have a DNA test, and things we haven’t identified yet can still show up.

Should I prioritize clinical or DNA testing? Both, where they make sense for your breed. They cover different kinds of risk and aren’t substitutes for each other.

Do older clearances still count? It depends on the test. For DNA tests, the panels add new tests over time, so retesting on a current panel or using the specific new tests that were added to a panel is worth thinking about.

Eye exams are only good for a year or two and need to be repeated, since new problems can develop as a dog ages.

For clinical tests like hips and heart, follow your breed club's recommendations on rechecks.

And keep in mind that any clinical test only tells you what was there on the day of the exam. Anything that develops after that is unknown until the next recheck.