IBD is often a diagnosis of exclusion, with no specific abnormal findings on a CBC, x-ray, or other biochemical test. If your dog has exhibited signs of gastrointestinal distress for more than a day, see your veterinarian.
Before diagnosing an IBD, the veterinarian will attempt to rule out other likely causes of gastrointestinal upset, including parasites, roundworms, or bacterial infections. A stool sample is the first diagnostic test that will usually be conducted. Examination of your dog’s feces could identify worms or parasites such as Giardia, and usually a course of antibiotics will be given to rule out a bacterial infection. However, if the antibiotics do not resolve the disease, IBD may be suspected.
Poor absorption of nutrients, such as protein and calcium deficiency, are a side effect of IBD and can be detected with a blood test. X-ray imaging can also reveal excessive gas or fluid in the GI tract, and swelling of the small intestine. Non-regenerative anemia (iron deficiency) also points toward a chronic condition, wherein the bone marrow is unable to replace blood cells quickly enough.
If no other obvious cause is uncovered by these tests, the veterinarian may order an endoscopy, where a camera mounted on a tube used to explore the esophagus, stomach and upper small intestine. Your dog will be sedated for this procedure and will experience only minimal discomfort. Biopsies (tissue samples) will be taken from a number of areas and examined microscopically for abnormally high immune cell counts and ulceration.
Finally, if no other bacterial or environmental toxins can be identified as the cause of the symptoms, the veterinarian will diagnose IBD.