Flank pain: is Intravenous Urogram necessary?

To determine the diagnostic yield of Intravenous Urogram (IVU) and the values of plain radiograph of kidney, ureter and bladder (KUB) and urinalysis as screening tests, with the objective to improve the cost effectiveness, in the management of patients presenting with flank pain due to urinary lithiasis.

All Intravenous Urogram (IVU) request forms and reports for the month of February 1998 were audited. The case notes, urinalysis, KUB and IVU films were traced and reviewed.

There were 110 patients investigated, 61.8% (68) had normal IVU, 38.2% (42) had abnormal IVU. The sensitivity and specificity of KUB alone was 79.4% and 90%. The sensitivity using urinalysis alone was 90.9% and its specificity 33.8%. The sensitivity of combined KUB and urinalysis was 100% and its specificity 26%, with a negative predictive value of 100%. All the patients with both negative KUB and urinalysis in our study were found to have negative IVU.

Our study shows that in patients with both negative KUB and urinalysis, the yield of IVU is very low and may not be necessary. This is important, as an IVU examination is not without risk. A combination of KUB with urinary analysis and careful evaluation of clinical symptoms will improve the cost-effectiveness of patient management.