To find out if a person has HD, the doctor will do one or more tests:
Barium Enema X Ray
An x ray is a black-and-white picture of the inside of the body. The picture is taken with a special machine that uses a small amount of radiation. For a barium enema x ray, the doctor puts barium through the anus into the intestine before taking the picture. Barium is a liquid that makes the intestine show up better on the x ray.
In some cases, instead of barium another liquid, called Gastrografin, may be used. Gastrografin is also sometimes used in newborns to help remove a hard first stool. Gastrografin causes water to be pulled into the intestine, and the extra water softens the stool.
In places where the nerve cells are missing, the intestine looks too narrow. If a narrow large intestine shows on the x ray, the doctor knows HD might be the problem. More tests will help the doctor know for sure.
Other tests to diagnose HD are manometry and biopsy:
The doctor inflates a small balloon inside the rectum. Normally, the anal muscle will relax. If it doesn't, HD may be the problem. This test is most often done in older children and adults.
This is the most accurate test for HD. The doctor removes and looks at a tiny piece of the intestine under a microscope. If the nerve cells are missing, HD is the problem.
The doctor may do one or all of these tests. It depends on the child.