There isn't any 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
Diagnosing Crohn's disease: Physical Exam and History
Your doctor will begin by gathering information about your health history and conducting a physical exam. Findings that may indicate further tests are needed include:
Diagnosing Crohn's Disease: Lab Tests
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:
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:
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.
Diagnosing Crohn's Disease: Colonoscopy or Sigmoidoscopy
Colonoscopy and sigmoidoscopy allow the doctor to directly view the large intestine, which is the lower part of the digestive tract. These techniques can often provide the most accurate information about the intestines. They may be better at detecting small ulcers or inflammation than other techniques. They can be used to assess the severity of any inflammation. Colonoscopy is the most important tool in diagnosing Crohn's disease.
During these procedures, a flexible viewing tube is placed through the anus into the large intestine. An image of the inside of the intestine is often projected onto a video monitor. A sigmoidoscopy involves examining the lowest part of the large intestine. A colonoscopy can provide a view of all of the large intestine and often the end of the small intestine, which is frequently affected by Crohn's. In either case, the doctor can directly view the colon to check for signs of ulcers, inflammation, or bleeding. The doctor can also take small samples of tissue to examine under a microscope, known as a biopsy. This helps determine whether the tissue shows signs of Crohn's disease or other problems.
Diagnosing Crohn's Disease: Video Capsule Endoscopy
For video capsule endoscopy, you swallow a small capsule or pill that holds a miniature video camera. As it travels through the small intestine, it sends images of the lining to a receiver you wear on a belt around your waist. The images are downloaded and reviewed at a computer. The images can provide detailed information about early, mild problems associated with Crohn's disease. This technique may be especially helpful if you have symptoms of Crohn's disease but barium X-rays do not show evidence of the condition.
While video endoscopy can provide valuable information, there are times when it may be best to avoid it:
- If you have an obstruction in the small intestine, the capsule could get stuck and make the obstruction worse.
- If you have a narrowing in the small intestine, such as from Crohn's disease, previous surgery, or previous radiation therapy, the capsule might become stuck.
- Some doctors worry that wireless transmissions from the capsule might interfere with implanted cardiac pacemakers or defibrillators.
Making a Diagnosis of Crohn's Disease
After the exams, lab tests, and imaging tests are done, your doctor will discuss the findings with you. If your doctor believes you have Crohn's disease, then you can work together to develop a treatment plan to manage the symptoms and control the disease.