Hematuria as an indicator for the presence or absence of urinary calculi

The purpose of this study was to determine whether the presence of hematuria or its absence can predict the presence or absence of urinary calculi as determined by computed tomography (CT) scan in patients presenting to the ED with acute abdominal colic. We reviewed the urine analysis and CT scans of all patients presenting to the ED over a 12-month period with acute colic and a clinical suspicion of urinary calculi. Urine samples were drawn on arrival in the ED before CT scanning. Two hundred seventy-seven patients were included in the study. The prevalence of urinary stones as detected by CT was 57.4%. The positive predictive value, negative predictive value, and accuracy for hematuria as a marker for stone disease was 60.9%, 72.4%, and 62.1%, respectively. A total of 3.24% of patients had some degree of obstruction, all of whom had hematuria. The absence of hematuria is not a reliable exclusion criterion for urinary calculi. The detection of urinary stones without hematuria does not imply obstruction.