Crohn’s diagnosis

Diagnosis

A healthcare professional will likely diagnose Crohn’s disease only after ruling out other possible causes for symptoms. There is no single test to diagnose Crohn’s disease.

A combination of tests may be used to help confirm a diagnosis of Crohn’s disease, including:

Lab tests

• Blood tests. Blood tests can check for signs of infection or anemia — a condition in which there aren’t enough red blood cells to carry enough oxygen to the tissues.These tests also may be used to check for levels of inflammation, liver function or the presence of inactive infections, such as tuberculosis. Blood also may be screened for the presence of immunity against infections.
• Stool studies. A stool sample may be used to test for blood or organisms, such as infection-causing bacteria or, rarely, parasites in the stool, to look for causes of diarrhea and symptoms. Sometimes looking for stool markers of inflammation, such as calprotectin, can be helpful.

Procedures

• Colonoscopy. A colonoscopy uses a tiny camera on the end of a flexible tube to visually examine the entire colon and the very end of the ileum. During the procedure, small samples of tissue, called a biopsy, may be taken for laboratory analysis. This may help to make a diagnosis. Clusters of inflammatory cells called granulomas may suggest a diagnosis of Crohn’s disease.
• CT scan. A CT scan is a special X-ray technique that provides more detail than a standard X-ray does. This test looks at the entire bowel as well as at tissues outside the bowel.CT enterography is a special CT scan that involves drinking an oral contrast material and getting intravenous contrast images of the intestines. This test provides better images of the small bowel and has replaced barium X-rays in many medical centers.
• MRI. An MRI scan uses a magnetic field and radio waves to create detailed images of organs and tissues. MRI used with a contrast fluid, called MR enterography, is particularly useful for evaluating a fistula around the anal area or the small intestine.Sometimes MR enterography can be performed to check for disease status or progression. This test may be used instead of CT enterography to reduce the risk of radiation, especially in younger people.
• Capsule endoscopy. This test involves swallowing a capsule with a camera in it. The camera takes pictures of the small intestine and sends them to a recorder worn on a belt. The images are then downloaded to a computer, displayed on a monitor and checked for signs of Crohn’s disease. The camera exits the body painlessly in stool.Endoscopy with biopsy may still be necessary to confirm a diagnosis of Crohn’s disease. Those with Crohn’s disease of the small intestine may be at a higher risk of the capsule getting stuck in the intestine, especially if there is a history of narrowing or surgery of the small intestine. Capsule endoscopy should not be done if there is a suspected stricture or blockage, also called an obstruction, in the bowel.

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