A diagnosis of necrotizing enterocolitis is based on your baby's medical history, symptoms, and:

• An abdominal X-ray, to provide a picture of the intestines. If your child has necrotizing enterocolitis, the X-ray may show a sausage-shaped intestine, often with air in the walls of the intestines.
• A fecal occult blood test, to check for blood in your baby's stool.
• A stool culture, to examine your baby's stool and to look for a specific kind of bacteria.
• A spinal fluid test, to determine the amount of blood cells, protein, glucose, and bacteria in the fluid around your baby's spinal cord.
• A blood culture, to identify any bacteria in your baby's blood.
• A urine test, to look for any signs of infection or bacteria in your baby's urine.

Monitoring necrotizing enterocolitis

After diagnosis, your baby may need to have more tests to monitor the disease, including:

• Abdominal X-rays. An abdominal X-ray can show whether the infection is improving or getting worse. X-rays are repeated every 6 to 8 hours.
• A paracentesis. If X-ray results are not clear, your doctor may take a sample of fluid from your baby's belly. If some of the contents of the intestines are found in this fluid, it means there is a hole in your baby's intestines.
• An abdominal ultrasound. This imaging test may be used to see if your baby's intestine is infected and inflamed.
• An arterial blood gas test. This test can tell whether your baby has enough oxygen in his or her blood.
• A complete blood count (CBC). This test looks at the different parts of your baby's blood to determine how well he or she can fight infection.

MRI tests are currently being studied for use in infants with severe necrotizing enterocolitis as a way to see how much intestinal tissue is damaged.² This is only at the research stage right now.