Crohn Disease

Is Testing Right for Me? I Have My Test Results

Crohn Disease

What Is Crohn Disease?

Crohn disease is a chronic illness that affects the digestive or gastrointestinal (GI) tract. The tissue in the GI tract gets irritated, inflamed, and swollen. Painful sores called ulcers develop and sometimes bleed. Usually, only part of the GI tract is unhealthy, and there is healthy tissue in between the ulcers and irritation.

Symptoms of Crohn Disease

  • Diarrhea, which often lasts for weeks or happens at night
  • Stomach pain
  • Weight loss 
  • Fatigue
  • Bleeding with bowel movements
  • Problems with growth and development in children
  • Fever
  • Inflammation of eyes, skin and joints
  • Low iron in the blood (anemia)
  • Sores around the anus

Describing Types of Crohn Disease

Doctors often describe how a person is affected by Crohn disease in two ways:

  • Location: Crohn disease can affect any part of the GI tract from the mouth to the anus. It usually affects the large intestine (the colon) and the end of the small intestine where it joins the colon (the ileum).
  • Disease behavior: The swelling and irritation that happens in Crohn disease can lead to ongoing problems. Sometimes, people have inflammation. Other people may get a buildup of tissue that narrows the GI tract, also called "strictures." Crohn disease may also develop into fistulas, which are places where the wall of the intestine has opened. Fistulas often get infected.

Long-Term Health Problems

There is no cure for Crohn disease. People who have this condition are treated for the symptoms with medicine and surgery. They often have periods where the disease gets worse, followed by periods where the disease is under better control. About 70% of people with Crohn disease will need surgery at some point.

People with Crohn disease have an increased risk of other health problems, including:

  • Lack of nutrition or low vitamin levels because of poor absorption in their GI tract
  • Problems in other parts of the body: arthritis, skin problems, kidney stones, gall stones
  • Higher chance to develop cancer in the GI tract
Next: Who Is at Risk for Crohn Disease?

To find out if genetic testing might change your medical care, check the box below that best describes you.

I think I might have Crohn disease because I have some of the symptoms, but I haven't seen a doctor yet.

I've been tested for disease, and I definitely have it.

I've been tested for Chron disease, but the results weren't clear. My doctor isn't sure whether I have it.

I'm at-risk for Crohn disease because a close family member has it. I don't have any symptoms of it right now.

I'm at-risk for Crohn disease because I'm Ashkenazi Jewish. I don't have any symptoms of it right now.

I don't have any symptoms or risk factors for Crohn disease, but I'm worried about whether I'll get it.

You told us that you think you might have Crohn disease, but you haven't seen a doctor yet. A genetic test is not the first step to diagnosing Crohn disease. If you have symptoms that could be Crohn disease, it is important for you to see a doctor. The doctor will ask you more about your symptoms, review your family and medical history, and order tests as needed.

You told us that you definitely have Crohn disease based on testing you've had done. Genetic testing may be useful for you. Results of genetic testing may give your doctor information that changes your medical care. Changes in the NOD2/CARD15 gene have been related to types of Crohn disease that:

  • Starts at a younger age
  • Affects the ileum, which is the lower part of the small intestine, just before it joins the large intestine
  • Is more likely to cause a narrowing or blockage of the GI tract. This may make you need surgery more often.

If you have genetic testing and one or more gene changes are found, your doctor may want to treat your symptoms more aggressively. This may mean a different choice of medicine or an earlier surgery.

If you have genetic testing and no gene changes are found, your doctor will continue to treat you based on your symptoms.

Before making a decision about Crohn disease genetic testing, you should consider the benefits, limitations, and possible uses for you. Learn more about the pros and cons of genetic testing for Chron disease.

You told us that you've had testing for Crohn disease that hasn't given you a clear answer. Genetic testing may be useful. Crohn disease and another, related condition called ulcerative colitis are both inflammatory bowel disease (IBD). This means that they can share some features. While other testing can often tell them apart, sometimes it is hard to tell one from the other. People who fall in this uncertain category are sometimes told they have "indeterminate colitis."

  • If you have genetic testing for Crohn disease and a gene change is found, it may "tip the scale" in favor of a diagnosis of Crohn disease.
  • If you have genetic testing for Crohn disease and a gene change is not found, these results probably won't be helpful. Only about 50% of people with Crohn disease have these gene changes, so you can have Crohn disease even if your test results don't find a gene change. Your doctor will continue to treat you based on your symptoms.

Before making a decision about Crohn disease genetic testing, you should consider the benefits, limitations, and possible uses for you. Learn more about the pros and cons of genetic testing for Chron disease.

You told us that you have a higher risk of Crohn disease because of your family history or ethnic group, but you don't have Crohn disease or any symptoms of it. Genetic testing is not likely to be useful for you.

At this time, genetic testing for Crohn disease is used to help confirm a diagnosis of Crohn disease, or to help make treatment decisions. It does not provide useful information for people who are only at risk for the condition. Even if you have a gene change associated with Crohn disease, there is no way to predict whether you'll get it. There isn't anything you can do to prevent it, either.

You can learn about the common symptoms of Crohn disease by reading What Is Crohn Disease?. If you develop any of them, you should see a doctor.

You told us that you are worried about getting Crohn disease even though you don't have any symptoms or risk factors for it. While genetic testing is technically possible for you, it generally isn't recommended. If your results are normal, it doesn't rule out the chance that you could get Crohn disease. If the results find a gene change, there is no way to predict whether you'll get it. There isn't anything you can do to prevent it, either.

You may wish to talk to a doctor who can address your concerns and answer your questions.