How Do Dog DNA Tests Work? Accuracy, Limits and Best Kits

For information only. This article supports, and never replaces, an examination by a veterinarian.

If you have a rescue dog, you may have lots of questions about your dog's background. Is that a shepherd in there? Why does she herd the kids? A dog DNA test can give you some answers, but only some. Breed results are an estimate, health results are a list of genetic findings rather than a diagnosis, and two companies can look at the same dog and disagree.

This guide covers what happens between the cheek swab and the report, what the results can and can't tell you, and how to pick a kit that fits your reason for testing.

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What are dog DNA tests?

DNA tests for dogs work much like human ancestry tests. A sample of your dog's cells goes to a lab, and the lab reports what it finds in your dog's genetic code. Genetic testing has been used in pets for more than 20 years, and most consumer kits today use a cheek swab you collect at home.

Most kits give you one or both of two very different kinds of information:

Breed ancestry: an estimate of which breeds make up your dog, based on how closely its DNA matches the company's reference dogs.
Health screening: a check for specific genetic variants (small changes in a gene) linked to certain diseases or to drug sensitivity.

Keep those two apart in your head. They answer different questions, and they carry different levels of certainty.

What does a dog DNA kit include?

Most consumer kits include:

A cheek swab or brush to collect cells from inside your dog's mouth.
Instructions on how to collect the sample and what to expect.
A return envelope or prepaid mailer.

Your kit may also ask you to register it online first, so the lab can match the sample to your dog.

How does dog DNA testing work?

First, you collect the sample. You rub the swab against the inside of your dog's cheek, let it dry or seal it as the instructions say, and mail it to the company's lab.

At the lab, the sample is genotyped. The lab reads many genetic markers, which are known spots in the DNA where dogs tend to differ from one another, and compares your dog's markers with the company's own reference panel: a database of DNA from dogs of known breeds. The closer your dog's markers match a breed in that panel, the more of that breed shows up in the report. If the sample doesn't contain enough DNA, the lab may ask you to swab again.

Results usually arrive in about 2 to 4 weeks, depending on the company. Wisdom Panel, for example, says 2 to 3 weeks.

The catch is that every company builds its own reference panel, so each one compares your dog against a different set of dogs.

Six steps from cheek swab to dog DNA report: register, swab, mail, lab reads markers, compares to its own panel, report in 2 to 4 weeks — Infographic by I Love Veterinary

How to collect a good DNA sample

The following video is a general demo of one oral collection device. Your kit may look different, so follow your own kit's instructions:

To recap the steps most kits share:

No food or treats beforehand. Waiting times differ between companies, so follow the time your kit gives, and check the mouth for food bits before you start.
Swab only your dog's mouth and don't touch the swab tip. This keeps other DNA, including yours or another pet's, out of the sample.
Restrain your dog gently if needed, and don't let it chew or bite the swab.
If your kit uses a tube with liquid, don't spill it. Let the swab dry or seal it exactly as the instructions say.

Breed results vs health results

What breed results can tell you

A breed result is a statistical estimate, not a fact written in your dog's genes. As veterinarian Dr. Lisa Moses told CBS Boston, breeds are defined largely by the way dogs look, and there isn't a genetic gold standard for what a breed is. Each company compares your dog with its own reference dogs, so results can disagree.

Two pieces of evidence show how much. In a 2024 study in the Journal of the American Veterinary Medical Association, researchers sent samples from 12 purebred dogs to six consumer DNA services. Five of the six always identified the registered breed, but predictions varied between tests, and one test's results followed the submitted photo more closely than the DNA. The authors advised caution and noted there is no industry standardization. A CBS Boston I-Team report sent one rescue dog's samples to three companies: all found German Shepherd, but at anywhere from 29% to 65%, with a different mix of other breeds each time.

So for a purebred dog, a good test will usually confirm what you know. For a mixed breed, read the percentages as that company's best estimate from its own database.

What health results can tell you

Health screening looks for specific variants linked to disease. A result that says your dog carries a variant is not a diagnosis. Some variants only cause disease when a dog inherits two copies (a dog with one copy is a carrier). Others don't always cause disease even when present, and how much a variant matters can depend on the dog's breed background.

A 2023 study of more than a million dogs, written by Wisdom Panel researchers, found that 57% of dogs carried at least one copy of one of the 250 disease-linked variants studied. Yet the authors found evidence that the variant reliably causes disease (full penetrance) for only 10 of them. They cautioned against making firm health care or breeding decisions from these results alone and recommended input from specialists or genetic counselors.

In a 2018 Nature commentary, summarized by Harvard Medical School's Center for Bioethics, Moses and two colleagues warned that many pet genetic tests rest on small studies. They described a pug that was euthanized after a test result when her signs fit a more treatable spinal disease. It's the worst case, and the reason at-risk results should go to your veterinarian before you act on them. Our guide to degenerative myelopathy covers one inherited condition in more detail.

MDR1: the health result your vet will want to know

MDR1 (also called ABCB1) is one health result with a direct, practical use. Dogs with the MDR1 mutation handle certain drugs differently: their bodies are less able to keep those drugs out of the brain and clear them, and they can have severe reactions to some common medications. The mutation is most common in herding breeds such as collies and Australian shepherds, long-haired whippets, several other breeds and a variety of mixed breeds.

If your dog's report shows MDR1 status, your veterinarian uses it when choosing medications. Tell every vet who treats your dog, including emergency clinics.

What DNA tests can't tell you

Whether your dog will get a breed-linked condition. Knowing your dog is part German Shepherd doesn't tell you if it will develop hip dysplasia. That question belongs to your veterinarian's exam.
Your dog's personality. A 2022 study in Science of more than 18,000 dogs found that breed explains only about 9% of the variation in behavior between individual dogs. A herding-breed result doesn't mean your dog will herd, and a "calm" breed doesn't guarantee a calm dog.
A diagnosis. Only your veterinarian can diagnose a disease, using your dog's history, an exam and, where needed, confirmatory tests.

What a dog DNA test can tell you, such as breed mix estimate and MDR1 status, and what it cannot, such as a diagnosis or personality — Infographic by I Love Veterinary

Who should see the results?

Your veterinarian, first. Health findings and MDR1 status can affect care and drug choices, and your vet can tell you which findings matter for your dog.

A trainer may find the breed mix interesting, but given that 9% figure, base training on how your dog actually behaves rather than on the breed list.

How to choose a dog DNA test

Start with your reason for testing:

Just curious about a mixed breed? A breed-only test answers that. You don't need a health panel.
Want health screening? Choose a breed + health test, and plan to go over any at-risk result with your vet before acting on it.
Have a herding breed or herding mix? Check whether MDR1 is included. Not every kit includes it, so read the kit's description.
Thinking about breeding? Work with your vet or a genetic counselor on which tests to run, rather than relying on a consumer kit alone.

Then compare the reference panel (a breed missing from it can't show up in your results), the health panel, extras like relative finders, any consult for at-risk findings, and turnaround. Take health panel counts loosely: some companies list more than one number on their own pages.

Dog DNA tests to consider

Our picks are based on specs, manufacturer information and published reviews, not on side-by-side testing. Independent studies don't name the most accurate brand, so there is no winner here. Specs come from each company and can change.

Embark Breed + Health Dog DNA Test

Best for: owners who want both breed ancestry and a broad genetic health screen.

Embark says its breed panel covers more than 400 breeds, types and varieties, including wolf, coyote, dingo and village dogs.
Adds a broad genetic health panel and trait reports to the breed results.
Includes a family tree going back to great-grandparents and a relative finder that can match your dog with tested relatives.
Developed with Cornell University College of Veterinary Medicine, according to the company.

Limitation: health findings need your vet's interpretation, and the company's "99% breed ancestry accuracy" figure is its own claim, not an independent result.

Check the Embark Breed + Health test on Amazon

Embark Breed ID Dog DNA Test

Best for: rescue and mixed-breed owners who mainly want to know what's in the mix.

Uses the same breed reference panel as Embark's health kit, according to the company.
Includes the family tree and relative finder.

Limitation: no health screening; you'd need a different kit for that.

Check the Embark Breed ID test on Amazon

Wisdom Panel Premium Dog DNA Test

Best for: owners who want the largest health panel in the Wisdom Panel range.

Wisdom Panel says it detects more than 430 breeds, types and varieties.
Screens for more than 200 genetic health conditions, according to the company, plus more than 50 traits.
Offers a genetic consult if your dog has an at-risk finding, according to the company.

Limitation: the company's own pages list different health test counts, so treat the number as approximate.

Check Wisdom Panel Premium on Amazon

Wisdom Panel Essential Dog DNA Test

Best for: owners who want breed results plus a basic health screen.

Same breed detection as Premium, according to the company.
A much smaller health panel, with the same trait reports.

Limitation: far fewer health tests than Premium. If health is your main reason for testing, compare the two panels first.

Check Wisdom Panel Essential on Amazon

Wisdom Panel Breed Discovery Dog DNA Test

Best for: owners of herding breeds or herding mixes who want breed results and MDR1 status.

Same breed detection as the other Wisdom Panel kits, according to the company.
Includes the MDR1 drug-sensitivity test.

Limitation: no broader health panel beyond MDR1.

Check Wisdom Panel Breed Discovery on Amazon

Dog DNA test FAQ

How accurate are dog DNA tests?

For purebred dogs, most tests in the 2024 JAVMA study identified the registered breed. For mixed breeds, results can vary between companies, and company accuracy figures are not independent measurements.

Can a dog DNA test diagnose a disease?

No. Carrying a variant doesn't mean your dog has or will get the disease. Your veterinarian decides what a finding means and whether more testing is needed.

Is a DNA test the same as a microchip or AKC DNA profile?

No. A microchip is a permanent ID that links your dog to you if it gets lost. The AKC DNA Profile program verifies identity and parentage, and the AKC says it does not determine breed or genetic health.

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This article is for general information and is not a substitute for advice from your veterinarian.