Plasma neutrophil gelatinase-associated lipocalin is an early marker of acute kidney injury in critically ill patients: a prospective study

Introduction

Serum creatinine is a late marker of acute kidney injury (AKI). Plasma neutrophil gelatinase (pNGAL) is an early biomarker of AKI after cardiac surgery. The purpose of this study was to assess the ability of pNGAL to predict AKI in ICU patients.

Methods

All patients admitted to three ICUs of the same institution were enrolled in this prospective observational study. pNGAL was analyzed at ICU admission. RIFLE criteria were calculated at admission and for each day during the first week. Patients were classified according to RIFLE criteria (RIFLE 0 or 1). Four groups were identified: RIFLE 0–0, 1–1, 1–0 and 0–1.

Results

During this 1-month period, 88 patients were included in the study. Thirty-six patients had RIFLE 0–0 with a mean pNGAL of 98 ± 60 nmol/l. Twenty-two patients had RIFLE 1–1 with a mean pNGAL of 516 ± 221 nmol/l. Twenty patients had no AKI at admission but developed AKI at 48 hours (24 to 96 hours) (RIFLE 0–1). In this case the mean pNGAL was 342 ± 183 nmol/l. Ten patients had RIFLE 1–0 and the mean pNGAL was 169 ± 100 nmol/l. With a cutoff value of 155 nmol/l, the sensibility and specificity to predict AKI were respectively 82% and 97%. Seven patients needed extrarenal therapy, all of them had pNGAL >155 nmo/l. The patients with pNGAL <155 nmol/l had more shock, more sepsis and a higher Simplified Acute Physiology Score II score.

Conclusion

pNGAL at ICU admission is an early biomarker of AKI in a setting in which the timing of kidney injury is unknown. pNGAL increases 48 hours before RIFLE criteria.