Background: According to controversial guideline for management in case of hemodynamically stable blunt abdominal injury with microscopic hematuria. Most of the patients could be omitted for abdominal computed tomography (CT). Despite high sensitivity and specificity of abdominal CT, in addition to high medical cost, there are risks from radiation exposure and adverse reaction from use of contrast media.
Objective: To evaluate the prevalence of KUB injury on abdominal CT in case of hemodynamically stable blunt abdominal injury with microscopic hematuria.
Material and Method: Forty-one studies of abdominal CT performed during 1 January 2010 and 30 June 2012 were retrospectively reviewed for KUB injury (categorized by AAST organ injury scale) by consensus of two experienced radiologists.
Results: KUB injury was found in 36.6% from all selected CT studies. Almost all cases could be managed conservatively. The cutoff point of microscopic hematuria at 20 cells/hpf has sensitivity 80% and specificity 46.15%.
Conclusion: One-third of the patients have KUB injury but almost all of them could be conservatively managed. We proposed that the cutoff point of hematuria be equivalent to or greater than 20 cells/hpf to be one of the indicators for predicting KUB injury that needs radiological evaluation; but it should be carefully considered along with clinical information.

Keywords: Abdominal computed tomography, KUB injury, Blunt abdominal injury, Microscopic hematuria