A combination of tests is used to establish a diagnosis of IBD. These include blood tests, endoscopic procedures and various radiological (x-ray) studies. Patients with IBD may require additional tests from time to time to monitor their progress, or to diagnose possible complications or the side effects of medications.
How is Crohn’s Disease Diagnosed?
No single test can establish the diagnosis of Crohn’s disease. The diagnosis is based on an expert clinician’s evaluation of the combined information obtained from the patient’s history, physical exam, results of laboratory tests, X-rays, and endoscopy and pathology test results. The endoscopic lesions show characteristic inflammation and ulcerations of the bowel mucosa (see Figure 4). An example of ulcerations of the small bowel lining can be seen using wireless capsule video endoscopy. A “tissue diagnosis” using endoscopically obtained biopsies is considered the “gold standard”. Stool specimens are usually tested to exclude the possibility that the intestinal inflammation is due to an infection with harmful organisms.
Figure 4: Endoscopic Appearance of Crohn’s disease.
Left: Localized ulcerations in mild colonic disease;
Right: More severe colonic disease with pseudopolyps
How is Ulcerative Colitis Diagnosed?
The diagnosis of ulcerative colitis is based on the patient’s clinical history, physical examination, and a series of tests. The first goal of these tests is to differentiate ulcerative colitis from infectious causes of diarrhea. Thus, stool specimens are analyzed to eliminate the possibility of bacterial, viral, or parasitic causes of diarrhea. Blood tests can check for signs of infection as well as for anemia, which may indicate bleeding in the colon or rectum. Patients generally undergo an endoscopic evaluation of the colon, or colonoscopy (see Figure 5). Biopsies are taken in order to distinguish ulcerative colitis from other diseases.