Giardia test kits are available for home or veterinary use to confirm a giardia diagnosis dogs case. A dog might need to take repeated tests over a period of time since it is possible that the infected dog was not shedding giardia cysts in the feces at the time the sample was taken. There is a dog giardia test kit available for home use that does not require a prescription called a Giardia Snap test.
Fecal examination under a microscope (called Direct Smear): This approach is primarily used with stools collected during bouts of diarrhea. Using this procedure, the veterinarian can identify the protozoa themselves (referred to as trophozoites). The trophozoite is shaped like a tear drop.
Concentration Methods: These methods include centrifugal zinc sulfate fecal flotation and immunofluorescence, which is a method that use s a fluorescent dye to make it easier to see the cysts if they are present in the feces. These approaches are used to determine if solid or semi-solid feces contain cysts. The cysts form around the trophozoite in the dog’s intestines as a protective cover before being excreted through the feces. The giardia cysts are 13um long. Feces examined must be under 30 minutes old.
Fecal ELISA: This testing approach uses enzymes that can detect Giardia antigens. Antigens are byproducts produced by the giardia protozoa which are found in feces taken from infected dog giardia patients. This test is commercially available for home use and is called a Giardia Snap test (see above).
Giardia Diagnosis During Routine Dog Health Exams
It is common for dogs that are asymptomatic to test positive for giardia after annual check-ups which include examination of the feces. When there is a positive giardia diagnosis in dogs, but no clinical symptoms, cases are only treated with medications at the discretion of the veterinarian and dog owner. Per guidelines published by the CAPC in 2010, dogs are not routinely tested for giardia if there are no clinical symptoms present.
Veterinarians will suspect dog giardia is other causes of related clinical symptoms such as moderate to severe diarrhea are seen and persists after other methods are used to cure the problem. Related giardia symptoms include weight loss, lethargy, overall loss of condition and failure to gain weight.
Giardiasis in Dogs and Cats: Diagnosis, Treatment, and Zoonotic Risk
Susan E. Little, DVM, PhD, Dipl. EVPC
Center for Veterinary Health Sciences
Oklahoma State University, Stillwater, OK, USA