Renal U/S Patient Information

What is a Renal or KUB Ultrasound?

A Renal or KUB ultrasound is an examination requested by your doctor to evaluate the urinary tract (which includes the kidneys, ureters, and urinary bladder). In the male patient, the prostate gland and seminal vesicles are also scanned.

What happens during my Renal or KUB Ultrasound?


A 6 hour fast is required prior to the test, and 1 litre of water needs to be drunk 1 hour prior to the allocated appointment time (to distend the bladder). Any previous X‐rays or scans should be brought along for comparative purposes.


The procedure takes about 30 minutes and will be performed in the ultrasound room by a sonographer. You will be asked to change into a gown but you will be covered except for the area required to be examined. A layer of warm gel will be spread over the area to be scanned to ensure good contact between the transducer and skin, and allows us to produce the best possible images.

The urinary bladder can only be properly assessed when full or distended as bladder volume measurements are taken whilst the bladder is full. Urine filling into the bladder from both right and left ureters is imaged to rule out any obstruction. The bladder and both kidneys are scanned after the bladder has been emptied to evaluate anatomical detail, and renal lengths are also measured.

In the male patient the prostatic volume is measured as well as images of the seminal vesicles taken.

What happens after my Renal or KUB Ultrasound?

At the end of the procedure the gel is simply wiped from your skin so that it does not mark your clothes. The images produced will be interpreted by one of our radiologists and the results forwarded to your doctor.