From the Research
A KUB ultrasound is a diagnostic imaging procedure used to evaluate the kidneys, ureters, and bladder for abnormalities or disease, and it is preferred over X-rays or CT scans in many cases due to its non-invasive nature and lack of radiation, making it safer for pregnant women and children. The purpose of this test is to assess these urinary tract structures for conditions such as kidney stones, tumors, blockages, infections, or anatomical abnormalities. During the procedure, a patient lies on an examination table while a technician applies a water-based gel to the abdomen and lower back area. The technician then moves a handheld device called a transducer across the skin, which emits sound waves that bounce off internal organs and create images on a monitor.
Key Points to Consider
- The procedure typically takes 30-45 minutes and requires some preparation, including drinking water before the exam to fill the bladder for better visualization, as noted in various studies 1, 2, 3.
- Patients may be asked to fast for several hours beforehand, though requirements vary by facility.
- No sedation is needed, and the procedure is painless except for possible mild discomfort from pressure applied with the transducer.
- According to a study published in 2004 1, KUB ultrasound is sensitive and specific for renal stones, with a sensitivity of 81% and specificity of 100%, and for hydronephrosis, with a sensitivity of 93% and specificity of 100%.
- Another study published in 1998 2 found that the combination of ultrasound and KUB correctly identified pathology consistent with nephroureterolithiasis with a sensitivity of 97.1% when compared with intravenous pyelography.
- A more recent study published in 2019 3 highlighted the effectiveness of non-contrast enhanced CT KUB in diagnosing renal colic, but also noted the importance of considering radiation dose and cost.
- The most recent and highest quality study 3 suggests that KUB ultrasound, possibly combined with other imaging modalities, remains a valuable tool in the diagnosis of urinary tract abnormalities, prioritizing patient safety and effective diagnosis.