Micturating cystourethrogram (MCUG) is also known as “voiding cystourethrogram” (VCUG). Both “micturating” & “voiding” both mean “passing urine”

What is it?

This test is carried out in the x-ray department and studies how the bladder fills up and then empties.

To do this test a fine tube (catheter) is passed into your child’s bladder through the urethra (the tube through which urine is passed) as in the diagram on the last page. X-ray dye is then put down the tube to show the outline of the bladder. This test is most commonly done in children under 1 year of age.

Why is it done?

We do this test to see if your child has ureteric reflux. This means the urine can pass up from the bladder towards the kidneys. Normally, this should not happen. Ureteric reflux can be a cause of urine infections.


Doing this test can put germs into the bladder. If your child is on Trimethoprim antibiotics you will need to give twice the normal dose on the morning of the test. Repeat this dose in the evening of the test and twice a day for the next 2 days. Then go back to the normal dose.

If your child is not on an antibiotic, or is on another one, please contact your paediatrician to ask what you should do.

What do we do?

You and your child will be given an appointment to go to the X Ray Department at. He or she will have the catheter passed by either a Paediatric nurse or doctor. This can sometimes be difficult in babies and can be uncomfortable. We do not give sedation as past experience tells us that this doesn’t usually work well. It often means a longer hospital stay as well. A local anaesthetic gel is used during the insertion of the catheter to ease any discomfort. You will be able to stay with your baby throughout the test.

The catheter will be taped in. You may be asked to feed your baby at this point to try and settle him/her.

The X-ray doctor will then put the dye down the catheter. This will distend the bladder and therefore may hurt for a short time. X-rays will be taken, these do not hurt. This normally takes about 15 minutes.

The catheter will be removed after the test. We may be able to tell you the results before you go home. If reflux is shown, your child may be started on a course of antibiotics. For this reason it would be helpful if your child could be weighed up to a week prior to your appointment by the health visitor and documented in your child’s red book, which we ask you to bring with you to your appointment.

If the results are not available on the day, your paediatrician will let you know them later at an outpatient appointment.

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