CT KUB (Stone Protocol)
A focused scan for Kidney stones, Ureter, Bladder.
Overview
Examines Kidney stones, Ureter, Bladder. Performed at an NABL-accredited Meridian Health centre with a same-day report and a free doctor review.
The full panel
3 areas across 1 groupEvery parameter, grouped by body system — no clicking to expand.
What this scan measures
A dedicated low-dose, non-contrast CT of the urinary tract — the stone protocol. It detects stones anywhere from the kidney to the bladder, measures them precisely, and shows secondary signs of obstruction such as a dilated collecting system or fat stranding around the kidney.
This is the definitive test for renal colic. Unlike ultrasound and plain films it finds essentially all stone types, including the uric acid stones that are invisible on X-ray, and it gives the two numbers that determine management: the size of the stone and how far down the ureter it has travelled.
Symptoms that lead to this scan
- Sudden severe loin pain radiating to the groin
- Blood in the urine, visible or on a dipstick
- Nausea and vomiting with flank pain
- Recurrent stone disease
- Pain with fever, which needs urgent assessment
Understanding your results
Stone size and position largely predict what happens next: small stones in the lower ureter frequently pass with fluids and medical therapy, while larger or more proximal stones more often need intervention. The scan also shows the degree of obstruction, which matters more than the stone itself — an obstructed, infected kidney is a urological emergency. Density measurements on CT give a hint about stone composition, which influences the choice of treatment. Management decisions belong with a urologist.
Why the preparation matters
No contrast and no fasting — and that is deliberate, because contrast in the urinary tract would appear bright and could mask the very stone being looked for. A moderately full bladder is helpful so that stones at the lower end of the ureter and in the bladder are easier to see. Remove metal from the waist and tell the team if you are or might be pregnant, since ultrasound is used instead in pregnancy.
CT Scan — safety and who should not be scanned
Full CT Scan guideCT uses considerably more ionising radiation than a plain X-ray — the trade for the detail it produces. Published reference figures put a head CT at roughly the background radiation of several months and a chest or abdominal CT at roughly a few years' worth. That is a risk worth taking when the scan will change management, and not worth taking when it will not, which is why CT is requested selectively rather than as a screening test. Modern scanners use iterative reconstruction and automatic dose modulation to keep the exposure as low as the diagnostic question allows.
- Pregnancy
- Always declare it. CT of the abdomen or pelvis delivers a direct dose to the fetus and is avoided unless the scan is genuinely necessary and no alternative — usually ultrasound or MRI — will answer the question. Head and limb CT can sometimes proceed with shielding after a specific discussion.
- Previous severe reaction to iodinated contrast
- A past reaction with rash, swelling, breathing difficulty or collapse must be reported before any contrast study. The scan may be done without contrast, with premedication, or replaced by a different test. Simple warmth, flushing or a metallic taste during a previous injection is a normal sensation, not an allergy.
- Impaired kidney function
- Iodinated contrast is cleared by the kidneys, so a recent creatinine or eGFR is checked before contrast studies. With significantly reduced function the scan may be done without contrast, or with hydration and dose adjustment as directed by the radiologist.
- Metformin, and uncontrolled thyroid overactivity
- Bring your medication list. Metformin is sometimes withheld around a contrast study in people with reduced kidney function, and iodinated contrast can destabilise untreated hyperthyroidism — both are managed with a plan rather than a refusal, provided the team knows.
- Inability to lie still, or claustrophobia
- The bore is short and open, so claustrophobia is far less of a problem than with MRI, but movement blurs the slices and may make a scan non-diagnostic. Tell the team if pain, tremor or anxiety will make stillness difficult; positioning aids and, rarely, sedation can be arranged.
- Table weight and bore limits
- Every scanner has a stated maximum table weight and aperture. Mention any concern when booking so the appropriate scanner is allocated, rather than discovering it on the day.
Who should consider this scan
- Anyone with acute severe flank pain suggestive of a stone
- People with recurrent stone disease
- Patients whose ultrasound or KUB was inconclusive
- Anyone with unexplained visible blood in the urine
- Patients being planned for stone treatment
Conditions it helps detect
How it works
Patient stories
96% recommend“The phlebotomist arrived exactly on time and was gentle. My report came in five hours with a doctor’s note.”
“Booked at night, sample collected next morning. The parameter breakdown is genuinely thorough.”
“Loved the free doctor review — she walked me through my vitamin D and thyroid results clearly.”