Kidneys, Ureter, Bladder (KUB)
all information

Kidneys, Ureter, Bladder (KUB)

(Abdominal X-ray; Flat Plate of the Abdomen)

En Español (Spanish Version)


This type of x-ray uses radiation to take a picture of structures inside the abdomen.

Parts of the Body Involved

  • Abdomen

Reasons for Procedure

  • To help diagnose the source of nausea, vomiting, pain or other symptoms related to the abdomen
  • To help detect and locate calcifications (ie, kidney stones )
  • To identify suspected urinary system problems, such as a kidney stone
  • To identify a blockage in the intestine
  • To locate a foreign object that has been swallowed
  • To assess whether there is air or fluid in the peritoneal space (the space surrounding the abdominal organs)

Abdominal Organs

3d male digestive organs

© 2008 Nucleus Medical Art, Inc.

Risk Factors for Complications During the Procedure

Women in early pregnancy should not be exposed to this procedure.

The following factors can interfere with the clarity of the x-rays:

  • Large amounts of gas or stool in the intestines
  • Excessive peritoneal fluid (fluid from the sac that lines the abdomen)
  • Obesity
  • Large calcified uterine fibroids
  • Dye or barium left from previous tests
  • Mass in either uterus or ovary

What to Expect

Prior to Procedure

You may be asked not to eat or drink anything for 4 hours before your exam.

You'll remove your clothes and put on a hospital gown. You'll also need to remove all metal-containing items, including jewelry and watches.

Tell your doctor if you:

  • Have taken any bismuth medications (such as Pepto-Bismol) within the last four days
  • Had a barium contrast media x-ray within the last four days
  • Have an IUD currently inserted
  • Are pregnant or could possibly be pregnant

During Procedure

There are no special interventions.



Description of the Procedure

You will lie flat on your back underneath the x-ray machine, and remain still while the x-ray is taken. You may be asked to shift to other positions for more x-rays (eg, on your abdomen or even standing).

After Procedure

You can resume normal activity.

How Long Will It Take?

The procedure takes about 10 minutes.

Will It Hurt?

There is no pain associated with this procedure.

Possible Complications

There are no known complications for this procedure.

Average Hospital Stay

The procedure is done as an outpatient. There is no hospital stay required.

Postoperative Care

You may resume all normal activity after the procedure.


The KUB may help your doctor identify the source of your pain. If these x-rays show a mass, blockage, or other abnormality, you may undergo further testing, which may include:

Call Your Doctor If Any of the Following Occurs

There are no complications associated with this procedure.


National Kidney and Urologic Diseases Information Clearinghouse

American Urological Association


Canadian Health Network

The Kidney Foundation of Canada


The Merck Manual website. Available at: .

The Patient's Guide to Medical Tests. Yale University School of Medicine; 1997.

Last reviewed March 2008 by Daus Mahnke, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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