Incidence and Significance of Negative Hematuria in Patients with Urolithiasis Visiting the Emergency Room with Flank Pain

ABSTRACT

PURPOSE: This research was conducted to determine the incidence of negative hematuria in patients with urolithiasis in Korea and the significance during evaluation of a patient' s complaining of flank pain. METHODS: We evaluated 363 consecutive patients who were suspected of having urolithiasis and who underwent intravenous urography (IVU). All patients underwent urinalysis and a urine dipstick test (UDT). We evaluated the sensitivity, the specificity, the positive predictive value and the negative predictive value of UDT, urinalysis and a combination of these two tests, and we compared the rates of incidence of negative hematuria. In addition, we estimated the relation between the RBC count and the severity of the ureteral obstruction. RESULTS: The IVU was positive in 206 of the 363 patients. The incidence of negative hematuria for urinalysis, UDT, and the combination were 9.2%, 8.7% and 6.3%, respectively. Thirteen patients (3.6%) had another disease. There was no correlation between the degree of ureteral obstruction and the incidence of negative hematuria (p= 0.713). Also, no correlation was established between the degree of ureteral obstruction and RBC count (p=0.742). CONCLUSIONS: In patients with urolithiasis, the incidences of negative hematuria for urinalysis, UDT and a combination of the two tests were 9.2%, 8.7% and 6.3%, respectively. The presence or absence of hematuria in patients with acute renal colic should not determine whether a more definitive study is performed.