Fecal testing: Don't be afraid to step in(to) it!
During his presentation on diagnostic test options for gastrointestinal (GI) disease in dogs as part of the technician program at a recent CVC, Scott Owens, DVM, MS, DACVIM, highlighted the technician’s role in this common area of disease—the arena of vomiting, diarrhea and the like.
Dr. Owens walked the audience through the steps of determining what’s going on in patients with GI issues. First and foremost is that “Please tell all!” patient history, which technicians are vital in gathering. Hear Dr. Owens explain some of the things to ask about, including presenting complaints, an acute versus a chronic longevity, concurrent diseases, diet and current medications.
But let’s get right to the poop. That fecal sample—so valuable. What can you do with it? Here’s a quick overview.
A fecal flotation is the cornerstone of examining a fecal sample, which can be done in-house or sent out to a laboratory. Dr. Owens says fecal floatation is especially important when the history reveals the dog has been in an environment where parasites can be present. Hear what can make or break this fecal evaluation from Dr. Owens and what piece of equipment can do wonders for diagnosis, if you do it frequently:
Here’s a handy how-to on fecal centrifugation.
Test it—and quick!
Two common culprits, giardiasis and parvovirus, are easy to pinpoint with enzyme-linked immunosorbent assay (ELISA) tests that require stool samples.
Maybe …. Dr. Owens says fecal cultures can be tricky to interpret. When does he perform one? If the pet is eating a raw meat diet and has evidently bloody stool, it may indicate a Salmonella species infection. It’s also important to know if Salmonella or Clostridium species are running rampant if the pet is in a home with immunocompromised people.
Analyze its DNA
The IDEXX Canine and Feline Diarrhea RealPCR panel just takes a swab of stool and can catch several viral, bacterial and parasitic causes. Since you can get a lot of positive results that may or may not be significant, Dr. Owens relies more on the findings of the physical examination and patient history. “But if I’m really struggling—if a dog has a strong indication of bacterial disease and has been in that environment—I’m going to use it,” Dr. Owens says.
Assess its protein content
If a protein-losing enteropathy is suspected, the fecal alpha-1 proteinase inhibitor test is a good go-to. It measures the amount of protein in the stool to show if the intestines are leaking this vital component, Dr. Owens says.
Examine it for blood
Blood in the stool can be hard to detect visually, which is where the fecal occult blood sample comes in. Since high protein in a pet’s diet can cause a false positive result, Dr. Owens says it’s best to feed a vegetarian diet for a few days before testing. The key to this test: A negative result is more informative. “If it’s negative, I’m really happy—there’s no bleeding,” he says. “If it’s positive, I shrug my shoulders and say, ‘OK, it could be, it could not be that blood is present.’”
Don't hesitate to step in
Fecal examinations are just a part of a workup in a patient with a GI issue. Blood testing, biopsy, endoscopy and ultrasonography are other routes to diagnosis.
“The role of the technician is really valuable in knowing and maybe even saying ‘Hey, you know, are we at that point? Do we need to think about biopsies?’” Dr. Owens says. “Taking that role in the hospital to have that comfort to say to the doctor, ‘What about this test?’ or ‘What about this test, I heard about this ….’ is really important.”