Fecal Tests for Dogs

Katie Grzyb, DVM
By Katie Grzyb, DVM on Sep. 16, 2022

Fecal testing for dogs is routinely performed to rule out intestinal parasites that may be invading your dog’s gastrointestinal (GI) system. Several types of intestinal parasites can infect dogs, and their effects vary depending on the type of parasite and the overall health of your dog.

Fecal testing may also be performed when your dog is having acute or chronic GI tract issues, in an attempt to investigate underlying causes of the clinical signs.

Unfortunately, you can’t usually see these parasites in your dog’s feces, as they prefer to stay in the body. The parasites do, however, shed microscopic eggs in the feces, which is why you need fecal testing to look for these eggs.

Diagnosing these parasites helps vets appropriately treat and clear them from the GI system, often before they become an issue for your dog’s health.

What Parasites Does a Fecal Test for Dogs Check for?

Fecal testing for dogs checks for intestinal parasites, including worms and microscopic parasites. Some of these parasites can transfer to humans (a condition called zoonosis), so it is very important that veterinarians keep your pet and your family as safe as possible.

Fecal testing assesses for the following parasites:

Roundworms are common parasites, and there are two main species that affect dogs: Toxocara canis and Toxascaris leonina. Adult worms are white, spaghetti-like worms that are several inches long. Roundworms can affect humans, especially children. This type of worm causes malnourishment, especially in puppies, as they feed on food that the dog has ingested. Common clinical signs are vomiting, diarrhea, weight loss, a pot-bellied appearance, and a dull hair coat.  

Hookworms are parasites that feast on the blood of their host. There are three main species that affect dogs: Ancylostoma caninum, Acylostoma braziliense, and Uncinaria stenocephala.

They are about 2 millimeters long and often difficult to see. This type of parasite can affect humans, especially children. These worms have hook-like mouth parts that attach to the intestinal wall and feed on blood. This causes intestinal inflammation and blood loss, which leads to vomiting, diarrhea, weight loss, poor hair coat, and anemia (low red blood cell count). Hookworms can also cause skin irritation and itching.

Usually, hookworms are found in dogs that have been in poor sanitary conditions, though Greyhounds are also an overrepresented breed for resistant hookworm infections.

Whipworms are common parasites, with Trichuris vulpis being the species that affects dogs. They are about 5-6 millimeters in length and have a tapered end that resembles a whip.

The thicker end embeds into the wall of the intestines, causing inflammation. Early stages of whipworm infection often have no clinical signs, but with continued inflammation, eventually a dog will develop diarrhea, weight loss, poor hair coat, weakness, blood in the stool, and/or anemia.  

Tapeworms are common in dogs, with Dipylidium caninum being the most common species that affects dogs. Their hook-like mouth parts attach to the walls of the intestines.

These worms can reach 30 centimeters in length and have segments (called proglottids) that are passed in the feces. These segments are about 12 millimeters long and look like moving grains of rice.

Tapeworms can only be transmitted by fleas, so the best way to prevent them is by keeping your dog on flea control medication. Clinical signs of infestation are usually minimal, such as itchiness around the anus and licking the hind end frequently. In puppies, clinical signs are more severe and include anemia, poor growth, and even blocked intestines.

Giardia is a protozoal parasite that may or may not cause symptoms. Dogs with healthy immune systems can clear it from their body without you noticing. Other dogs may have diarrhea, weight loss, abdominal pain, dull hair coat, decreased appetite, or vomiting. This parasite is contagious to humans and causes similar clinical signs.

Coccidia is a protozoal parasite that can also cause no clinical signs in healthy adult dogs, but it causes diarrhea, vomiting, failure to gain weight, poor hair coat, and lethargy in puppies or immunocompromised adult dogs.

How Much Does a Dog Fecal Test Cost?

The cost of fecal testing can range from $30 to $75. This depends on if the testing is performed in the clinic the same day, sent out to a lab for testing, or run in an emergency or routine setting.

How Often Does My Dog Need a Fecal Test?

Adult dogs should have fecal testing performed every 6 months. Puppies require more frequent parasitic testing, since their immune systems are not fully formed.

Heartworm preventatives (not including the ProHeart vaccine) contain deworming agents that help to control parasitic infections in dogs on a monthly basis.

It is still important for routine testing for two reasons: Breakthrough infections can occur, and protozoal parasites and some worms are not controlled with the ingredients contained in the heartworm preventatives.

How to Collect a Dog's Stool Sample

Use a small bag (poop collection bag or plastic bag) to collect a small amount of fresh feces after your dog poops. Seal the bag immediately. Your veterinarian may also give you a fecal test tube to collect feces.

This sample is good for up to 8 hours unrefrigerated, or 12-24 hours if kept in the fridge. Wash your hands after obtaining the sample. If you store the sample in the fridge, use a disinfectant wipe to clean the area where the sample was placed to avoid any zoonotic spread of disease.

Your veterinarian may perform a rectal examination or use a small plastic fecal loop to obtain a sample of feces if you are unable to collect a sample prior to your appointment. 

How Is a Fecal Test for Dogs Done?

Fecal testing should be performed on fresh feces (obtained within 12-24 hours of testing). The fresh fecal sample is mixed with a special solution in a container. This mixture is then allowed to sit for several minutes to allow parasitic eggs, if present, to float to the top of the sample. A small amount of the top layer is then assessed under a microscope to diagnose the presence of worm and parasitic eggs.

Some veterinary teams perform this test in the hospital with results within 15-30 minutes, and others will send a fecal sample to a laboratory for parasite and Giardia testing, which takes 24-48 hours for results to return.

It is important to perform this test to determine the exact type of intestinal parasite affecting your dog. Dewormers are not always effective for every type of parasite, and protozoal parasites often require specific therapies to clear them from the body. 

Diagnosing the type of parasite helps determine the best therapy:

Featured Image: iStock.com/SeventyFour


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Katie Grzyb, DVM


Katie Grzyb, DVM


Dr. Katie Grzyb received her Doctorate of Veterinary Medicine from Ross University in 2009. She continued her clinical training at...

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