X-ray beams are passed through the abdomen, producing images of the kidneys, ureters, and bladder on a special type of film. KUB radiography is often used as a first step in diagnosing problems of the urinary system, and is usually done in conjunction with intravenous pyelography.

Purpose of the KUB Radiography

  • To determine the size, shape, and position of the kidneys and bladder
  • To detect obvious abnormalities of the urinary system, such as kidney stones
  • To help differentiate between urologic and gastrointestinal diseases, which both produce abdominal pain
  • To locate a foreign object (e.g., that has been swallowed)
  • To detect air or fluid in the space surrounding the abdominal organs (peritoneal space)

Who Performs KUB Radiography

  • A radiologist or a qualified technician

Special Concerns about KUB Radiography

  • Pregnant women should not undergo this test because exposure to ionizing radiation may harm the fetus.
  • The presence of severe obesity, gas or feces in the intestine or residual barium in the abdomen from a recent contrast x-ray study may interfere with clear visualization of the urinary system.

Before the KUB Radiography

  • Tell your doctor if you had a barium contrast x-ray or have taken medication containing bismuth, such as Pepto-Bismol, within the last four days as this may interfere with the test.
  • Tell your doctor if you have an intrauterine device (IUD).
  • Tell your doctor if you are pregnant or may be pregnant.
  • Do not eat or drink anything for 4 hours before the test.
  • You will be asked to disrobe, remove any jewelry or metal objects, and put on an x-ray gown.
  • In men, the testes may be covered with a lead apron to prevent irradiation.

What You Experience during KUB Radiography

  • You will be positioned on your back or stomach on a table, with your arms overhead, under an x-ray machine.
  • You will be asked to take a deep breath and hold it while the x-ray is being taken, in order to provide a clear view of the abdomen. It is important to remain still throughout the procedure because any motion can distort the image.
  • The procedure takes several minutes.

Risks and Complications of KUB Radiography

  • X-ray exams involve minimal exposure to radiation.

After the KUB Radiography

  • You may return home and resume your usual activities.

Results of KUB Radiography

  • X-ray films are usually ready shortly after the test is completed. A radiologist will examine the images for abnormalities.
  • A definitive diagnosis can rarely be made based on a KUB study alone. In most cases, additional tests—such as ultrasound or intravenous pyelography—are required in order to establish a diagnosis and determine the extent of the problem.


The Johns Hopkins Consumer Guide to Medical Tests

Simeon Margolis, M.D., Ph.D., Medical Editor

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 17 Jan 2012

Last Modified: 16 Mar 2015