L-FABP can be an early marker of acute kidney injury in children.

Background: Acute kidney injury (AKI) is a common postoperative complication following cardiopulmonary bypass (CPB) surgery. New biomarkers to identify patients with early AKI (before increases in serum creatinine) are needed to facilitate appropriate treatment. This study aimed to test the role of urinary liver fatty-acid-binding protein (L-FABP) as an early biomarker for AKI in children undergoing CPB surgery.

Methods: This is a case-control study of children undergoing CPB. AKI was defined as 50 % increase in serum creatinine at 48 h after surgery. For each patient, five serum and urine samples were obtained corresponding to time 0 h (presurgery) and 2, 6, 24, and 48 h after surgery.

Results: Twenty-seven patients, median age 360 days, were enrolled. AKI developed in 11 patients (41 %); three needed renal replacement therapy (peritoneal dialysis); there were two deaths. There were significant differences between patients with and without AKI in L-FABP levels at 2, 6, and 48 h after surgery, length of hospital stay, and CPB time; there were no differences in gender, patient age, and body weight. L-FABP was normalized to urinary creatinine concentration at all time points, with area under the receiver operator curve (AUC ROC) 0.867 at 2 and 6 h postoperatively. Correlation coefficient between L-FABP and length of hospital stay after surgery was statistically significant (r = 0.722, p value = 0.000).

Conclusions: Our results suggest that urinary L-FABP can be used to diagnose AKI earlier than rise in serum creatinine in children undergoing CPB.