What is a renal ultrasound or kidney ultrasound?
A renal ultrasound (also called a kidney ultrasound or urinary tract ultrasound) is a non-invasive scan that uses high-frequency sound waves to create images of your kidneys, bladder and ureter.
It helps doctors look at the size, shape, structure and function of the kidneys.
What does a renal ultrasound involve?
The scan uses a device called a transducer, which is moved over your abdomen to take images of your kidneys and bladder. Men may also have their prostate gland checked during the test.
It is the same type of scan that women have during pregnancy.
It’s carried out as a day procedure in hospital and usually takes about 10 to 30 minutes.
Who is it for?
A renal ultrasound may be requested if you have signs or symptoms of kidney problems, such as abnormal kidney function tests, urinary tract infections (UTIs), urinary incontinence or blood in your urine. It may also be used as part of routine CKD assessment and monitoring.
An ultrasound can give your doctor more detailed information than blood tests alone. For example, it can show whether the kidneys are small or scarred, or whether there are any blockages in the urinary tract.
Is it safe? Are there any alternatives?
Ultrasound is very safe and should be painless. Unlike some other imaging tests, it doesn’t expose you to any radiation or contrast dye, so it’s suitable for everyone, including during pregnancy, and can be repeated as needed.
Alternatives or follow-up tests include CT scans or MRI scans, which may be suggested when more detailed imagery is needed.
A renal ultrasound gives useful information but can’t diagnose every condition, so you may need further tests.
Where will a renal ultrasound take place?
The ultrasound is usually performed by a trained sonographer (ultrasound practitioner) in the hospital imaging or radiology department.
What happens before the renal ultrasound? How do I prepare?
You’ll need a full bladder for the scan to be successful, so you’ll be asked to drink around 1 litre (2 pints) of fluid – ideally water – beforehand.
Wear loose, comfortable clothing so the healthcare team can easily access your abdomen.
Your hospital will send specific guidance with your appointment details.
What happens during the scan?
- You will lie on a bed, and staff will apply a gel to your abdomen and lower back.
- The transducer will be moved over the area. Sometimes you may be asked to change position or hold your breath briefly for clearer images.
- The first part of the test will be carried out while your bladder is full. You’ll usually be able to empty it once your bladder’s been checked.
- The procedure is painless but can be uncomfortable for the time you have a full bladder, and pressure from the transducer can feel firm if an area is tender.
What happens immediately after the renal ultrasound?
After the ultrasound, the gel is wiped off, and you can usually go home straight away. No recovery time is needed because the scan is non-invasive.
What should I expect when I get home?
You can eat, drink and go back to your normal activities immediately.
How will I get the results?
The sonographer will review the images and may consult a radiologist, a doctor who specialises in interpreting images. They will prepare a report for the doctor who referred you, which typically takes around a week. The hospital team may be able to tell you on the day of the test how long they think it’s likely to take to send out the results.
You’ll get the results at your next appointment with your GP or kidney doctor.
Is there anything else I need to know?
It’s important you don’t empty your bladder before the scan. If you’re concerned about travelling to the hospital with a full bladder, you can arrive an hour early and drink the necessary fluids while you’re there.
Publication date: 02/2026
Review date: 02/2029
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