Role of white blood cell and neutrophil counts in predicting spontaneous stone passage in patients with renal colic

OBJECTIVE To determine the clinical, imaging and laboratory variables that can predict spontaneous passage of ureteral stones causing renal colic and the role of white blood cell (WBC) and neutrophil counts for the prediction of spontaneous calculi passage. PATIENTS AND METHODS A total of 156 patients who were referred to the emergency department complaining of renal colic due to a ureteral stone entered the analysis. Several clinical, laboratory and imaging parameters were evaluated for their potential ability to predict stone passage in a time interval of 1 month. The study design had two objectives. Primarily we analyzed all patients irrespective of stone size and secondly we analyzed patients with calculi of 10 mm maximum length. RESULTS Spontaneous stone passage was observed in 96 (61.5%) patients in the overall population and in 84 (65.1%) of 129 patients with calculi <10 mm. Increased concentrations of serum WBCs and neutrophils at the time of the acute phase of a renal colic were associated with increased likelihood of spontaneous passage. In the multivariate analyses we found that WBC and neutrophil counts were the most important predictors of stone elimination. CONCLUSIONS Active surveillance of patients suffering from ureteral lithiasis is an acceptable option. Identifying the parameters which can predict those patients who will mostly benefit from this is of great importance. Based on our results, WBC and neutrophil counts should be considered when patients with renal colic secondary to ureteral calculi are evaluated since they can significantly add to spontaneous elimination prediction. Their consideration in addition to other important factors, like stone size and location, would maximize their predictive ability.