There isn't one test that can tell you whether or not you have Crohn's disease. And Crohn's disease has many possible symptoms that are the same as symptoms for other health problems. So, to make a diagnosis of Crohn's disease, your doctor is likely to gather information from multiple sources. You'll probably go through a combination of exams, lab tests, and imaging studies with these goals in mind:
rule out other health problems that have similar symptoms
make a clear diagnosis of Crohn's disease
determine exactly which part of the digestive tract is affected
Your doctor may request lab tests in order to look for any problems that might be linked to Crohn's disease. These tests check for signs of infection, inflammation, internal bleeding, and low levels of substances such as iron, protein, or minerals. Lab tests may include:
blood protein levels
blood sedimentation rates
body mineral levels
red blood cell counts
stool samples to check for blood or infectious microbes
white blood cell counts
Diagnosing Crohn's Disease: Imaging Studies and Endoscopy
Crohn's disease may appear anywhere along the gastrointestinal tract from the mouth to the rectum. X-rays and other images can help identify the severity and location of Crohn's disease. These studies may include the following:
barium X-rays and other X-rays
colonoscopy or sigmoidoscopy
video capsule endoscopy
Diagnosing Crohn's Disease: Barium X-rays and Other X-rays
A barium X-ray can show where and how severe Crohn's disease is. It is especially helpful for finding any problems in parts of the small intestine that can't be easily viewed by other techniques.
A chalky fluid containing barium is given by mouth or through the rectum. When barium fluid is given by mouth, it is called an upper GI series. When barium fluid is placed in the rectum, it is called a barium enema. The barium fluid flows through the intestines, appearing white on X-ray film. This makes it easier to view problem areas. On a barium X-ray, your doctor may be able to see ulcers, narrowed areas of the intestine, abnormal connections between organs, known as fistulae, or other problems.
If barium X-rays show some sign of disease, your doctor may request other X-rays or imaging studies. These X-rays can help identify exactly how much of your digestive tract is affected by Crohn's disease.
Diagnosing Crohn's Disease: CT Scans
CT scanning uses computer-aided X-ray techniques to produce more detailed images of the abdomen and pelvis than can be seen in traditional X-rays. CT scans can help detect abscesses that might not show up on other X-rays. Abscesses are small pockets of infection.