Fecals are microscopic examinations of your pet's feces, carried out in your veterinarian's office. The primary goal of a fecal exam is to identify and treat any intestinal infections that could be compromising your pet's overall health.

Fecal exams are used to determine if your dog or cat has intestinal parasites such as hookworms or roundworms. Parasites not only make pets uncomfortable and irritable, they could lead to more serious conditions for your pet or even be transmitted to family members. Intestinal parasites live in your pet’s gastrointestinal tract, hidden from view. Annual fecal exams are the quickest and most reliable way to test your pet for intestinal parasites.

Source: https://www.wcrah.com/site/blog-flat-rock-vet/2019/07/14/why-should-my-pet-have-a-fecal-exam