A diagnosis of intussusception is usually based on the child's symptoms. If it is suspected, the health professional will do a physical exam. As part of the physical exam, the health professional examines the child's:

• Abdomen, for a tender, sausage-like lump, which suggests telescoping of the intestine. This lump may be difficult to detect, especially if the child is crying.
• Rectum, for the presence of blood or signs of bleeding or bulging of tissue into the rectum (prolapse).

An X-ray of the abdomen is usually done as well. An abdominal X-ray may show nothing unusual in the child's intestines, or it may show signs of a blockage in the intestine.

If the child has rectal bleeding, and an abdominal X-ray strongly suggests the condition, the diagnosis is likely to be intussusception.

Ultrasound of the abdomen and an air or barium enema are used to confirm a diagnosis of intussusception.

Ultrasound of the abdomen

An ultrasound of the abdomen can determine whether intussusception is present and show how much swelling there is in a child's intestinal wall.

Air or barium enema

During an enema, air or barium (a milky-white liquid) is flushed through a child's rectum into the intestines. If intussusception is present, X-rays taken during the enema will show a blockage or a small opening in the affected part of the intestine.

• Enemas using air rather than barium are generally preferred in babies and young children.
• Because of the risk of intestinal rupture during an enema, this procedure should only be done in a hospital where surgical access is immediately available.
• An air or barium enema is also used as a treatment to help clear the intestinal blockage.

A computed tomography (CT) scan of the abdomen is helpful in diagnosing intussusception in adults. It is rarely done in children.