An abdominal X-ray is a picture of structures and organs in the belly (abdomen). This includes the stomach, liver, spleen, large and small intestines, and the diaphragm, which is the muscle that separates the chest and belly areas. Often two X-rays will be taken from different positions. If the test is being done to look for certain problems of the kidneys or bladder, it is often called a KUB (for kidneys, ureters, and bladder).

X-rays are a form of radiation, like light or radio waves, that are focused into a beam, much like a flashlight beam. X-rays can pass through most objects including the human body. When X-rays strike a piece of photographic film, they make a picture. Dense tissues in the body, such as bones, block (absorb) many of the X-rays and look white on an X-ray picture. Less dense tissues, such as muscles and organs, block fewer of the X-rays (more of the X-rays pass through) and look like shades of gray on an X-ray. X-rays that pass only through air, such as the lungs, look black.

An abdominal X-ray may be one of the first tests done to find a cause of belly pain, swelling, nausea, or vomiting.

Why It Is Done

An abdominal X-ray is done to:

• Look for a cause of pain in the belly or ongoing nausea and vomiting.
• Find a cause of pain in the lower back on either side of the spine (flank pain). An abdominal X-ray can show the size, shape, and position of the liver, spleen, and kidneys. Other tests (such as ultrasound, CT scan, or intravenous pyelography) may be used in addition to look for more specific problems.
• Find an object that has been swallowed or put into a body cavity.
• Confirm the proper position of tubes used by your doctor in your treatment, such as a tube to drain the stomach (nasogastric tube), a feeding tube in the stomach, a tube to drain the kidney (nephrostomy tube), a catheter used for dialysis, a shunt to drain fluid from the brain into the stomach (V-P shunt), or other drainage tubes or catheters.

How To Prepare

Before the X-ray test, tell your health professional if you:

• Are or might be pregnant. An abdominal X-ray is not usually done during pregnancy because of the risk of radiation exposure to your baby (fetus). Many times an abdominal ultrasound is done instead.
• Have had an X-ray test using barium contrast material (such as a barium enema) or have taken a medicine (such as Pepto-Bismol) that has bismuth in the last 4 days. Barium and bismuth can block a clear picture.

You may be asked to empty your bladder before the test. You may need to take off any jewelry that may be in the way of the X-ray picture, such as if you have a pierced belly button.

You will need to sign a consent form that says you understand the risks of an X-ray and agree to have the test done. Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).