Neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker of renal injury in patients with ureteric stones: a pilot study

Objective: The role of neutrophil gelatinase-associated lipocalin in renal obstruction remains unclear. The aim of this study is to assess neutrophil gelatinase-associated lipocalin kinetics and its potential role as a biomarker of renal damage in acute ureteric colic. Methods: Thirty-six patients with acute ureteric colic were prospectively recruited and compared with two control groups. Blood and urine samples for plasma neutrophil gelatinase-associated lipocalin and urinary neutrophil gelatinase-associated lipocalin levels were obtained at various time points. Results: There were significantly higher levels of urinary neutrophil gelatinase-associated lipocalin and the urinary neutrophil gelatinase-associated lipocalin/creatinine ratio at presentation when comparing patients with acute ureteric colic to healthy controls ( P=0.002 and P=0.004, respectively). In patients with acute ureteric colic managed with surgical intervention ( n=27) there was a significant reduction in plasma neutrophil gelatinase-associated lipocalin ( P=0.001) and an increase in the urinary neutrophil gelatinase-associated lipocalin/creatinine ratio 6 hours postoperatively ( P=0.03). Eight of nine patients managed conservatively for acute ureteric obstruction had spontaneous stone passage at follow-up (median 26 days) with a significant reduction in the urinary neutrophil gelatinase-associated lipocalin/creatinine ratio ( P=0.03). Conclusion: The observation of a reduction in plasma neutrophil gelatinase-associated lipocalin and urinary neutrophil gelatinase-associated lipocalin levels following relief of renal obstruction due to ureteric stones suggests the potential role of neutrophil gelatinase-associated lipocalin as a biomarker in this scenario and in the follow-up setting as a potential marker of relief of obstruction. Level of evidence: 3b