Diagnostic utility of microhematuria in renal colic patients in emergency medicine: correlation with findings from multidetector computed tomography

Abstract

Although urine analysis is a simple and inexpensive method for the initial evaluation of renal colic patients presenting in emergency departments, it is regarded as unreliable for an exact diagnosis of urinary system stones. The aim of the present study is to assess the association between clinical demographics, and stone size and location, with the combined utility of urinalysis and unenhanced multidetector computed tomography (MDCT) in the emergency department. After gaining local Ethics Committee approval, a retrospective study was conducted with data from 186 patients who presented at our emergency service with flank pain and documented urolithiasis. Stone location and size was determined by MDCT, and the presence of microhematuria confirmed by urinalysis. The presence of hydronephrosis and clinical complaints were also recorded. A total of 186 patients were included in the present study, in which an absence of microhematuria was recorded in 24.7% patients. Urine density was found to be elevated in the microhematuria group (p=0.001). Upper urinary tract stones and hydronephrosis were found to be associated with the presence of microhematuria. Although statistically insignificant, an increased trend of microhematuria was observed with stones over 5 mm in size. Urinary stone size and location are directly associated with the incidence of microhematuria. Absence of microhematuria does not preclude MDCT imaging, however, especially in cases where stones are suspected in patients with renal colic.