Pediatric reference ranges for acute kidney injury biomarkers

Pediatr Nephrol. 2015 Apr;30(4):677-85. doi: 10.1007/s00467-014-2989-y. Epub 2014 Oct 28.


Background: Novel urinary biomarkers are useful for the prediction of acute kidney injury (AKI). Most promising are the urine markers NGAL, IL-18, KIM-1, and LFABP. Each of these has shown considerable promise diagnosing AKI earlier than serum creatinine (Scr) using disease controls. We set out to determine reference levels of these markers in a healthy pediatric population.

Methods: Urine was collected from 368 healthy children and assayed for NGAL, IL-18, KIM-1, and LFABP using commercially available kits or assay materials. Analysis of biomarkers by linear regression and according to age groups (3-<5 years; 5-<10; 10-<15; 15-<18) was performed to determine if biomarker levels differed with age and gender.

Results: Median values were: NGAL (6.6 ng/ml; IQR 2.8-17), IL-18 (21.6 pg/ml; IQR 13.6-32.9), KIM-1 (410 pg/ml; IQR 226-703), LFABP (3.4 ng/ml; IQR 1.6-6.0). Significant gender differences were found with NGAL and IL-18 and significant age differences were found with all markers. 95th percentile values for each marker varied with age and gender greater than median values.

Conclusions: This is the largest pediatric reference range study for the urinary measurement of NGAL, IL-18, KIM-1, and LFABP and highlights age and gender differences in these markers. This information is essential for rational interpretation of studies and clinical trials utilizing these emerging AKI biomarkers.

Publication types

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

MeSH terms

  • Acute Kidney Injury / diagnosis*
  • Acute Kidney Injury / urine*
  • Acute-Phase Proteins / urine
  • Adolescent
  • Biomarkers / urine*
  • Child
  • Child, Preschool
  • Fatty Acid-Binding Proteins / urine
  • Hepatitis A Virus Cellular Receptor 1
  • Humans
  • Interleukin-18 / urine
  • Lipocalin-2
  • Lipocalins / urine
  • Membrane Glycoproteins / urine
  • Proto-Oncogene Proteins / urine
  • Receptors, Virus
  • Reference Values


  • Acute-Phase Proteins
  • Biomarkers
  • Fatty Acid-Binding Proteins
  • HAVCR1 protein, human
  • Hepatitis A Virus Cellular Receptor 1
  • Interleukin-18
  • LCN2 protein, human
  • Lipocalin-2
  • Lipocalins
  • Membrane Glycoproteins
  • Proto-Oncogene Proteins
  • Receptors, Virus