Most gut parasites cannot be seen by looking at the stool, so the vet has a sample tested for worm eggs and for parasites too small to see. The Companion Animal Parasite Council asks for at least four stool tests in the first year of life and at least two a year for a healthy adult. A clear result only means that nothing was found in that sample, which is one reason the test is repeated.
The American Veterinary Medical Association names the common gut parasites as roundworms, hookworms, whipworms and tapeworms, plus two single-celled ones, coccidia and Giardia. It says that, apart from some tapeworm infections, you cannot tell that a pet has them by looking at the stool.
The association says part of the sample is looked at under a microscope for worm eggs and single-celled parasites. The parasite council also lists tests for proteins that the parasites give off, called antigens, and says they can find worms that are not laying eggs yet.
The veterinary association says roundworm infections can pass to people, and that children are at particular risk. Which parasites spread to whom is on What can I catch from my pet? What each worm does to a dog or a cat is on Does my pet have worms, and which ones?
Ask the clinic first. The veterinary association says the vet may ask for a fresh sample, or may take a small one straight from your pet's rear end. These steps come from the Merck Veterinary Manual, Kansas State University's Veterinary Health Center and the parasite council.
The manual gives the reasons. After more than six hours at room temperature a sample is no longer fit to test, because worm eggs develop and hatch. A sample that has lain on soil or grass for a long time can be invaded by tiny worms that live in the soil. Kansas State adds that some parasites are found best in a fresh sample that has not been chilled, so ask how the clinic wants it kept.
| Who says it | Puppies and kittens | Adult dogs and cats |
|---|---|---|
| Companion Animal Parasite Council, 2025 | At least four tests in the first year. | At least two a year, adjusted for health, travel, time outdoors and contact with other animals. |
| American Veterinary Medical Association | Ideally four times a year or more. | Ideally twice a year or more. |
| American Animal Hospital Association, for dogs, 2019 | Four in the first year. | One to four a year, depending on the preventive the dog takes and how it lives. |
| American Animal Hospital Association, for senior pets, 2023 | Not covered | One to four a year for dogs, and one to two a year for cats. |
For cats, the 2021 guideline that the animal hospital association wrote with the feline practitioners strongly recommends a stool test for kittens, and leaves the timing for adult cats to each cat's health and way of life. For cats that never go outdoors, the parasite council's site for owners asks for a stool check at the very least once a year.
No product covers every parasite. The veterinary association says dewormers and other preventive products do not work on the single-celled parasites, coccidia and Giardia. Which worms each product covers is on Which flea, tick and heartworm protection does my dog need?
A positive result is the clear one. The veterinary association says that if worm eggs or tapeworm segments are found in the sample, the pet has adult worms, and the vet will recommend a deworming program.
A clear result is weaker. The Merck manual says parasites are passed off and on, so for an animal with signs, one clear test is not enough to rule them out. To rule them out it asks for three samples, taken three days in a row or spread over seven to ten days.
The figures Petipedia could source for vet prices are on What does a vet bill cost? The national average for a stool test is in the cost table on When is my pet a senior, and what should the checkup include?
Kansas State calls the stool test essential for any animal with diarrhea, weight loss or vomiting, so those are reasons to call now. The veterinary association says puppies and kittens are at high risk of severe hookworm disease, which can cause blood loss that threatens life. Stool colors are sorted by urgency on Vomit, stool and urine: what the color means, and the signs that cannot wait are on Is this an emergency?
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Sources read on 2 October 2026; every number is as the source gives it.