A KUB scan (Kidneys, Ureters and Bladder ultrasound) is a quick, non-invasive and radiation-free way to check the urinary tract for stones, blockages, swelling (hydronephrosis), cysts and bladder issues. It’s often the first step in investigating urinary symptoms and monitoring known kidney or bladder conditions. Ultrasound uses sound waves (not X-rays), so there’s no ionising radiation risk.
What is a KUB Scan?
A KUB scan is an ultrasound of the kidneys, ureters and bladder. It produces real-time images of the urinary tract to assess structure and drainage. It differs from CT-KUB (Computed Tomography) or X-ray KUB, which uses ionising radiation. Ultrasound is safe in adults, children and during pregnancy.
Why do doctors recommend a KUB scan?
Doctors recommend a KUB ultrasound to investigate symptoms such as flank pain, visible or microscopic blood in urine, recurrent urinary tract infections (UTIs), urinary urgency or frequency, or reduced kidney function. It can:
- Detect kidney stones (bright echoes with acoustic shadowing).
- Show hydronephrosis (swollen kidney from obstruction).
- Assess bladder wall and residual urine after voiding (post-void residual, PVR).
- Monitor chronic kidney disease, cysts, tumours, or post-surgery changes.
What happens during a KUB ultrasound?
During the scan, you’ll lie on an examination couch. Warm gel is applied to your abdomen and pelvis. A probe (transducer) is moved gently across your skin to capture images. It takes 15–30 minutes, involves no needles or radiation, and the procedure is painless.
At RAD Clinics, scans are carried out by trained clinicians using high-resolution equipment, with CQC registration and branches in Northampton and Milton Keynes.
Do you need to fast for a KUB scan?
For a focused renal/bladder scan, fasting is not required. A full bladder is essential — drink 0.5–1 litre of water 30–60 minutes before the scan and avoid urinating. For combined abdominal and renal scans, fasting for 6–8 hours may be required to reduce bowel gas. Always follow the preparation details sent in your appointment confirmation.
What can a KUB ultrasound show in the results?
Findings may include:
- Kidney stones: visible as echogenic foci with shadowing (though very small stones in the ureter may be missed).
- Hydronephrosis: dilated renal pelvis or calyces suggesting obstruction.
- Bladder problems: wall thickening, diverticula, or high post-void residual volume.
- Cysts or masses: helps differentiate simple cysts from complex lesions.
The report may recommend further imaging (CT or MRI) if findings are unclear or require confirmation.
What’s the cost of a private kidney (KUB) scan?
In the UK, private KUB ultrasound prices typically reach up to £350. The actual price may vary depending on whether the scan is booked as a standalone service or as part of a combined abdominal and pelvic package.
At RAD Clinics:
- Offers competitive pricing for abdominal and pelvic scans.
- The package includes a report and same-day results.
- Discounts may apply if multiple scan areas are booked.
- No GP referral is required.
- Quick booking and shorter wait times compared to NHS pathways.
How are KUB scan results delivered?
Private clinics usually provide a written report and images within 1–3 working days. Many offer same-day verbal feedback, and some also provide same-day written reports.
At RAD Clinics, reports are delivered promptly by regulated clinicians, with aftercare guidance and secure booking systems.
How does KUB ultrasound compare to CT, MRI and X-ray?
Different imaging options for the urinary tract have distinct roles. The table below compares Ultrasound, CT, MRI and plain X-ray KUB:
| Imaging Type | Advantages | Limitations |
|---|---|---|
| Ultrasound (US) | No radiation, safe in pregnancy, quick, good for hydronephrosis and bladder volume, first-line test. | Less sensitive to small ureteric stones; image quality is affected by bowel gas or obesity. |
| CT-KUB (Non-contrast CT) | Highest sensitivity and specificity for stones (>95%), shows exact size/location, and detects alternative diagnoses. | Involves ionising radiation, has a relatively higher cost, and is not always the first choice for children/pregnancy. |
| MRI | No radiation, excellent soft-tissue detail, useful for complex cases or contraindications to CT. | Not routinely used for stones, more expensive, longer scan time, and less availability. |
| X-ray KUB (Plain film) | Quick, inexpensive, useful for tracking known radio-opaque stones (e.g. calcium stones). | Misses radiolucent stones (e.g. uric acid), involves radiation, poor soft-tissue detail, not first-line anymore. |
Where can I get a KUB scan privately?
Private KUB ultrasounds can be booked directly at CQC-registered clinics. RAD Clinics offers renal and urinary tract scans, as well as combined abdominal & pelvic packages, with branches in Northampton and Milton Keynes, professional reporting, and online booking.
Book your consultation today at our clinics in Milton Keynes and Northampton and take the first step towards a pain-free, active lifestyle.
Conclusion
A KUB ultrasound scan is a safe, quick, and effective first-line tool for evaluating the kidneys, ureters, and bladder. It is especially valuable in diagnosing stones, obstruction, and bladder problems without radiation exposure. While CT remains the gold standard for small stones and X-ray still has a role in monitoring certain stones, ultrasound is the safest and most practical first step.
RAD Clinics provides accessible, high-quality imaging with rapid reporting, ensuring you get answers quickly and safely.
Common Questions We Hear From Patients
How much is a private kidney scan in the UK?
A private kidney (renal and urinary tract) ultrasound at RAD Clinics costs £160.
What are the results of a KUB scan?
KUB scan results describe kidneys, ureters, and bladder, identifying stones, cysts, obstruction, hydronephrosis, infections, masses, and post-void residual volume.
Is an empty stomach required for a KUB ultrasound?
An empty stomach is not required at RAD Clinics; arrive with a full bladder after drinking 1–1.5 litres of water about one hour before your appointment.
Will I feel pain during a KUB ultrasound?
You will not feel pain during a KUB ultrasound; the non-invasive procedure involves only light probe pressure on the abdomen and pelvis.