Urinary neutrophil gelatinase-associated lipocalin as a biomarker to monitor renal function in patients with obstructive ureteral calculi.

Abstract

Our study aimed to investigate the clinical significance of urinary neutrophil gelatinase-associated lipocalin (NGAL) as an effective real-time monitoring biomarker of renal function in patients with obstructive ureteral calculi presenting renal colic. A cohort of 89 first-visit patients with renal colic caused by unilateral ureteral calculi were retrospectively reviewed. 46 of which received double-J ureteral stent placement (group 1) and the remaining 43 treated conservatively with analgesics and hydration (group 2) when diagnosed. Urinary NGAL (uNGAL) values in the baseline, 2h and 1day after treatments were recorded. The variation of this parameter over time and the association with patients' characteristics were analyzed. uNGAL levels decreased as time went by for patients receiving double-J ureteral stent placement (47.23 ± 28.32ng/mL for baseline, 40.73 ± 21.86ng/mL for 2h and 34.67 ± 18.00ng/mL for 1day after operation; p = 0.0363). Nevertheless, for those treating conservatively, the levels emerged a mild increase (50.63 ± 32.30ng/mL, 56.00 ± 32.01ng/mL and 60.63 ± 34.08ng/mL, correspondingly; p = 0.3708). By analyzing the association between uNGAL variation and patients' characteristics of group 1, operation duration showed the best correlation coefficient (Pearson r = 0.6106, r2 = 0.3728, p < 0.0001). uNGAL can be used as a biomarker to monitor the renal function effectively when serum creatinine (sCr) was within normal limits. And double-J ureteral stent can be considered as a protective factor to renal function in patients with obstructive ureteral calculi presenting renal colic.