Diagnosis (2024)

Your doctor will ask you about your symptoms and do a physical exam. You may also have X-rays and lab tests to find out if you have Crohn's disease.

It may go undiagnosed for years, because symptoms usually develop gradually and it doesn't always affect the same part of the intestine.

Other diseases can have the same symptoms as Crohn's disease. But doctors can diagnose Crohn's by doing a test that looks at the inside of the intestine and doing a biopsy.

Diagnostic tests

Biopsy.

This test is done on a sample of tissue collected during a colonoscopy. Bowel biopsies are painless (other than the possible discomfort of the scope procedure). They remove only a tiny piece of tissue.

Colonoscopy or flexible sigmoidoscopy.

Colonoscopy is often the preferred test because it can be used to examine the entire colon. Sigmoidoscopy reaches only the lowest part of the colon.

Abdominal X-ray.

This test can show possible obstructions in the belly.

Upper gastrointestinal (UGI) tests.

A UGI series examines the upper part of the digestive tract. A UGI endoscopy looks at the interior lining of your esophagus, stomach, and duodenum.

Barium enema.

This test looks at the large intestine (colon).

Computed tomography (CT) scan.

This test uses X-rays to make detailed pictures inside the body.

Magnetic resonance imaging (MRI).

MRI uses a magnetic field and pulses of radio wave energy to provide pictures of organs and structures inside the body.

Standard blood tests and urine tests.

These check for too few red blood cells (anemia), inflammation, or malnutrition. Depending on the symptoms, an erythrocyte sedimentation rate (ESR, or sed rate) or C-reactive protein (CRP) blood test may be done to look for infection or inflammation.

Other tests

Other tests may be done to confirm or evaluate the disease.

Stool analysis.

This may be done to look for blood, signs of bacterial infection, malabsorption, parasites, or the presence of white blood cells. It can help tell the difference between Crohn's disease and irritable bowel syndrome (IBS), which can have similar symptoms.

Video capsule endoscopy (VCE).

This test takes pictures of the digestive tract using a tiny camera that you swallow. The images are recorded by a device that you wear on your belt. The test allows your doctor to see the small intestine, which is hard to see with other tests.

Small bowel enteroscopy.

This test uses a long, lighted flexible tube with a tiny camera that sends pictures of the small intestine to a video screen. This helps the doctor look at the small intestine. The doctor can also take small samples of the tissue.

Blood tests to find antibodies.

These tests can sometimes help the doctor tell if you have Crohn's disease or ulcerative colitis. These tests include anti-neutrophil cytoplasmic antibody with perinuclear staining (pANCA), anti-Saccharomyces cerevisiae antibody (ASCA), and outer membrane porin C (Omp C).