Liver fatty acid-binding protein as a biomarker of acute kidney injury after cardiac surgery

Kidney Int. 2008 Feb;73(4):465-72. doi: 10.1038/ Epub 2007 Dec 19.


Acute kidney injury (AKI) is a major complication of cardiac bypass surgery. We examined whether levels of liver fatty acid-binding protein (L-FABP) can be an early biomarker for ischemic injury by measuring this protein in the urine of 40 pediatric patients prior to and following cardiopulmonary bypass surgery. AKI was defined as a 50% increase in the serum creatinine from baseline, which was normally not seen until 24-72 h after surgery. Enzyme-linked immunosorbent assay analysis showed increased L-FABP levels (factored for creatinine excretion) of about 94- and 45-fold at 4 and 12 h, respectively, following surgery in the 21 patients who developed AKI with western blot analysis, confirming L-FABP identity. Univariate logistic regression analyses showed that both bypass time and urinary L-FABP were significant independent risk indicators for AKI. After excluding bypass time from the model and using a stepwise multivariate logistic regression analysis, urinary L-FABP levels at 4 h after surgery were an independent risk indicator with the area under the receiver-operating characteristic curve 0.810, sensitivity 0.714, and specificity 0.684 for a 24-fold increase in urinary L-FABP. Our study shows that urinary L-FABP levels represent a sensitive and predictive early biomarker of AKI after cardiac surgery.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acute Disease
  • Acute-Phase Proteins / urine
  • Albuminuria / diagnosis
  • Biomarkers / blood
  • Biomarkers / urine
  • Cardiopulmonary Bypass / adverse effects*
  • Child, Preschool
  • Fatty Acid-Binding Proteins / blood
  • Fatty Acid-Binding Proteins / urine*
  • Female
  • Humans
  • Ischemia / diagnosis*
  • Ischemia / etiology
  • Kidney / blood supply*
  • Kidney Diseases / diagnosis*
  • Kidney Diseases / etiology
  • Lipocalin-2
  • Lipocalins / urine
  • Male
  • Postoperative Complications / diagnosis*
  • Postoperative Complications / etiology
  • Proto-Oncogene Proteins / urine


  • Acute-Phase Proteins
  • Biomarkers
  • Fatty Acid-Binding Proteins
  • LCN2 protein, human
  • Lipocalin-2
  • Lipocalins
  • Proto-Oncogene Proteins