At a glance
A renal ultrasound is an imaging test that uses sound waves to create pictures of the kidneys and the nearby urinary structures, including the bladder and ureters (the tubes that carry urine from the kidneys to the bladder).
A small handheld device called a transducer is pressed gently against the skin over the abdomen or back. It sends out high-frequency sound waves that bounce off the internal structures and return as echoes. A computer converts those echoes into a live image on a screen, letting the doctor see the size, shape, and internal texture of each kidney without any cuts or radiation.
Medical Condition
Doctors request a renal ultrasound whenever they need a quick, safe look at the kidneys or bladder to explain symptoms, confirm a diagnosis, or monitor a known condition.
- Persistent or severe pain in the flank (the side of the body between the ribs and the hip)
- Blood in the urine (haematuria)
- Recurrent urinary tract infections
- Suspected kidney stones
- A palpable mass or swelling felt in the abdomen
- Unexplained deterioration in kidney function, detected through blood tests
- Monitoring of known kidney cysts (fluid-filled sacs) or tumours
- Hydronephrosis (swelling of a kidney caused by a build-up of urine)
- Assessment before or after a kidney biopsy or transplant
- High blood pressure that may have a kidney-related cause
- Routine follow-up for children born with urinary tract abnormalities
There are very few situations where a renal ultrasound cannot be used, but there are cases where it gives limited information. Ultrasound does not show small stones in the ureter as reliably as a CT scan, and it cannot fully evaluate kidney function on its own. In those situations, your doctor will usually request additional tests alongside the ultrasound.
Risks & Complications
A renal ultrasound carries no known health risks because it uses sound waves, not radiation or needles, so there is nothing to inject and no tissue is disturbed.
- Mild, temporary skin discomfort from the pressure of the transducer, which passes immediately after the scan
- The gel applied to the skin may feel cold or slightly sticky, but it wipes off easily
- In rare cases, the images are not clear enough for a firm diagnosis, for example in patients with a higher body weight or with a lot of intestinal gas, and a repeat scan or a different imaging test may be needed
Preparation & Procedure
Preparation for a renal ultrasound is straightforward and depends on exactly which structures the doctor wants to examine.
If the bladder is included in the scan, you will usually be asked to arrive with a full bladder. This typically means drinking a set amount of water in the hour before the appointment and not urinating until the scan is done. For a kidney-only scan, a full bladder is not always required, but the radiologist (imaging specialist) may still prefer it. Fasting is generally not needed unless your hospital specifically requests it.
You do not need to stop any regular medications before the scan. Wear comfortable, loose-fitting clothing so the technician can easily access your abdomen and lower back.
No special pre-scan blood or urine tests are required solely for the ultrasound itself. However, if the scan is being done to investigate kidney function, your doctor may have already ordered a blood test measuring creatinine (a waste product that reflects how well the kidneys filter blood) beforehand.
The procedure itself usually follows these steps:
- You lie on an examination table, usually on your back, and may be asked to roll onto your side at different points
- The sonographer (ultrasound technician) applies a clear, water-based gel to the skin over your abdomen and lower back to help sound waves travel easily
- The transducer is moved slowly across the skin in several directions while the sonographer captures images
- You may be asked to take a deep breath and hold it briefly so the kidneys move into a clearer position
- If the bladder is being assessed, images are taken before and sometimes after you urinate
- The gel is wiped off, and you can get dressed immediately
- The sonographer sends the images to a radiologist, who writes a report for your referring doctor, usually within one or two days
Aftercare
A renal ultrasound requires no recovery time. You can eat, drink, drive, and return to all normal activities the moment the scan ends.
- No wound care is needed because the skin is never broken
- You can resume any medications as normal; none need to be held for the scan
- Drink normally after the scan, especially if you were asked to restrict fluids beforehand
- Your doctor will discuss the results with you at your next appointment or by phone, once the radiologist's report is ready
- If the scan reveals a finding that needs follow-up, such as a cyst, stone, or area of concern, your doctor will explain the next step, which may be a repeat ultrasound, additional imaging, a blood or urine test, or a referral to a nephrologist (kidney specialist)
- No specific lifestyle changes are triggered by the scan itself; any recommendations will come from the diagnosis your doctor makes based on the results
Cost & What Determines It
The cost of a renal ultrasound varies considerably depending on where it is performed and the clinical context surrounding it, even though the scan itself is technically straightforward.
- Hospital class and country: the same scan performed at a public hospital, a private clinic, and a private international hospital in different countries can differ significantly in price
- Outpatient versus inpatient setting: a scan done during a hospital admission is usually billed differently from one done at an outpatient imaging centre
- Scope of the scan: a kidney-only scan may be priced differently from a combined abdomen and pelvis scan that includes the bladder and surrounding structures
- Urgency: an emergency or after-hours scan often carries a higher fee than a routine scheduled appointment
- Radiologist reporting fees: in some hospitals the scan and the specialist interpretation are billed separately
- Additional imaging required: if the ultrasound is inconclusive and a CT or MRI is needed on the same visit, that will add to the total cost
- Accompanying blood or urine tests ordered at the same time
A hospital package for a renal ultrasound typically covers the scan itself, the gel and disposables, and the radiologist's written report. What tends to be billed separately includes the consultation with the referring or specialist doctor, any blood tests ordered the same day, and additional imaging if it becomes necessary.
BPJS Kesehatan and most Indonesian private insurance policies do not cover medical procedures performed abroad, so patients who travel for this scan generally pay out of pocket or hold a private international health insurance plan that explicitly includes overseas treatment. Before travelling, ask the hospital for a written cost estimate that lists every item individually. This is the most reliable way to know what you will pay and to avoid unexpected charges on the day.
Frequently Asked Questions
Does a renal ultrasound hurt?
A renal ultrasound is painless for most people. The sonographer (the technician who performs the scan) presses a small handheld device called a transducer against your skin and moves it gently over your back and sides. You may feel mild pressure, but there are no needles, no radiation, and nothing enters your body.
How do I prepare for a renal ultrasound, do I need to fast?
Your doctor will usually ask you to drink several glasses of water before the scan and avoid urinating so your bladder is full, as this gives a clearer view of the kidneys. Fasting is not always required for a renal ultrasound, unlike some other abdominal scans, but follow the specific instructions given by your hospital because preparation can vary slightly. Wear loose, comfortable clothing on the day.
How long does a renal ultrasound take?
The scan itself usually takes between 20 and 45 minutes, depending on how many structures the doctor needs to examine. You can eat, drink, and go about your normal day immediately afterwards. There is no recovery time needed.
How much does a renal ultrasound cost?
The cost of a renal ultrasound depends on the class of hospital or clinic you choose, whether the scan is done alongside other tests, and the radiologist's fee for reading and reporting the images. Requesting a written cost estimate directly from the hospital before your appointment is the most reliable way to know what you will pay.
This page is general information, not a substitute for medical advice. Every case is different. Your doctor decides what is right for you.
