From the Guidelines
A KUB is a radiographic examination that stands for "Kidneys, Ureters, and Bladder," primarily used to detect kidney stones, among other abdominal abnormalities. This plain X-ray of the abdomen provides images of the urinary tract structures, as well as other abdominal contents like the spine, parts of the intestines, and calcifications 1. The KUB X-ray is a quick, painless procedure with minimal radiation exposure, typically requiring the patient to lie on their back while the X-ray machine captures the image, and no special preparation is usually required.
Key Points About KUB
- KUB has limitations, as it doesn't show soft tissue detail well, so it's often used as an initial screening tool before more advanced imaging like CT scans or ultrasounds are ordered 1.
- The sensitivity of KUB for detecting urolithiasis is influenced by factors such as stone composition, location, and size, as well as patient body habitus and overlying bowel contents 1.
- Compared to noncontrast CT, digital radiography has been shown to be 72% sensitive for large (>5 mm) stones in the proximal ureter but only 29% sensitive overall for the detection of stones of any size in any location 1.
- A more recent study found that KUB detected only 8% of stones 5 mm relative to noncontrast CT, although a detection rate of 78% at KUB was observed overall for stones >5 mm 1.
Clinical Use of KUB
- KUB X-rays are particularly valuable in emergency settings when a quick assessment of the abdomen is needed.
- They can suggest the etiology for renal colic if a calcification is visible in the expected location of the ureter on the side of the patient’s pain 1.
From the Research
Definition of KUB
- A KUB (Kidneys, Ureters, and Bladder) radiograph is an imaging test used to visualize the kidneys, ureters, and bladder 2.
- It is often used in the diagnosis and management of patients with ureteral stones 2.
Purpose of KUB
- The purpose of a KUB radiograph is to aid in the interpretation of future KUBs, particularly when used in conjunction with computed tomography (CT) scans 2.
- It can help urologists determine stone outcome and reduce the need for additional imaging 2.