Urinalysis and bedside renal ultrasound are effective, safe, and less expensive than repeat CT scans

“Doctor, EMS just brought a man who is really uncomfortable into bay 4. He looks like he has a kidney stone, and he’s had one before. Can I give him some morphine?”

“Sure, put him in for a CT, and I’ll see him in a few minutes.”

Every day, emergency departments across the United States care for similar patients. Kidney stones affect one in 11 adults in the United States, and their prevalence has increased 40 percent in the past decade. Renal colic accounts for more than 700,000 emergency-department visits annually, and in 2009, 71 percent of these patients underwent CT examination. Depending on how it’s measured, the use of CT for renal colic has increased between three- and tenfold in the last two decades.^1,2

Among patients presenting with recurrent acute renal colic, should non-contrast CT of the abdomen be the standard diagnostic approach?

CT of the abdomen is the preferred diagnostic test to identify kidney stones due to its accuracy, speed, and widespread availability. Sensitivity ranges from 94 percent to 100 percent, while specificity ranges from 92 percent to 100 percent. CT is the test of choice for patients presenting with first-time renal colic or potentially complicated renal colic (eg, fever, a single kidney, or immunosuppression). Additionally, in patients in whom you suspect a serious alternate cause of their flank pain (eg, dissecting abdominal aortic aneurysm), CT should be performed. However, while CT is useful to detect extra-renal pathology, the rapid increase in CT use has not resulted in an increased incidence of alternate pathologies.