Urine neutrophil gelatinase-associated lipocalin identifies unilateral and bilateral urinary tract obstruction

Background. Urinary tract obstruction (UTO) is a common problem that can lead to permanent loss of kidney function. Unilateral UTO may be difficult to diagnose. Urinary neutrophil gelatinase-associated Lipocalin (uNGAL) may identify unilateral and bilateral UTO. Methods. Retrospective case-control study of patients undergoing hospital admission at three sites. UTO was determined by review of medical records and cases were matched to control patients. uNGAL was measured by immunoblot. Results. Twenty-four unilateral UTO and 15 bilateral UTO cases were identified. Admission serum creatinine (sCr) (milligram per decilitre) was significantly higher in bilateral UTO, 2.0 (1.1-5.3), but not unilateral UTO, 1.1 (0.8-1.5), compared to controls, 0.9 (0.8-1.2). uNGAL (nanogram per millilitre) was significantly higher both in patients with bilateral UTO, 140 (40-450), and unilateral UTO, 50 (20100), compared to controls, 20 (10-45). Discussion. uNGAL identifies kidney injury in unilateral and bilateral UTO even in the absence of an elevated sCr.