Reference Range of Urinary Neutrophil Gelatinase-Associated Lipocalin in Very Low-Birth-Weight Infants: Preliminary Data

ABSTRACT

We sought to determine the reference range for urinary neutrophil gelatinase-associated lipocalin (UNGAL) in very low-birth-weight (VLBW) infants with uncomplicated clinical courses. Samples of urine from 53 VLBW infants between 3 and 28 days of life were prospectively collected weekly for measurement of UNGAL. A subset of 22 infants with uncomplicated medical courses without risk factors for renal impairment was selected for study. Mean ± standard deviation and range for birth weight and gestational age of study infants were 1156 ± 191, 790 to 1440 g and 29 ± 2, 27 to 33 weeks, respectively. The 95th and 99th percentiles for UNGAL concentration from this group of infants were 25 ng/mL and 75 ng/mL, respectively. Bootstrapped mean 95th and 99th percentile values and their standard errors and 95 percent confidence intervals in ng/mL were 33.1 ± 13.0 (7.7, 58.6) and 67.5 ± 15.1 (37.9, 97.1), respectively. These values fall within the adult reference range. UNGAL values were stable across the ranges of gestational and postnatal age of the study infants. A preliminary reference range for UNGAL in VLBW infants has been established. Further investigation with more frequent urine collections in a larger population of VLBW infants that includes those with birth weights < 750 g and gestational ages < 27 weeks is necessary to confirm this reference range.

KEYWORDS

Renal impairment - acute renal failure - very low-birth-weight infant - neutrophil gelatinase-associated lipocalin

REFERENCES

• 1 Kjeldsen L, Johnsen A H, Sengelov H, Borregaard N. Isolation and primary structure of NGAL, a novel protein associated with human neutrophil gelatinase.  J Biol Chem. 1993;  268 10425-10432
• 2 Yang J, Goetz D, Li J Y et al.. An iron delivery pathway mediated by a lipocalin.  Mol Cell. 2002;  10 1045-1056
• 3 Mori K, Lee H T, Rapoport D et al.. Endocytic delivery of lipocalin-siderophore-iron complex rescues the kidney from ischemia-reperfusion injury.  J Clin Invest. 2005;  115 610-621
• 4 Mishra J, Dent C, Tarabishi R et al.. Neutrophil gelatinase-associate lipocalin (NGAL) as a biomarker for acute renal injury after cardiac surgery.  Lancet. 2005;  365 1231-1238
• 5 Zappitelli M, Washburn K K, Arikan A A et al.. Urine neutrophil gelatinase-associated lipocalin is an early marker of acute kidney injury in critically ill children: a prospective cohort study.  Crit Care. 2007;  11 R84
• 6 Lavery A P, Meinzen-Derr J K, Anderson E et al.. Urinary NGAL in premature infants.  Pediatr Res. 2008;  , [Epub ahead of print] PMID: 18552711
• 7 Bundgaard J R, Sengelov H, Borregaard N, Kjeldsen L. Molecular cloning and expression of a cDNA encoding NGAL: a lipocalin expressed in human neutrophils.  Biochem Biophys Res Commun. 1994;  202 1468-1475