title: Preliminary reference intervals for cystatin C and beta-trace protein in preterm and term neonates.
abstract: OBJECTIVE
  To determine the reference intervals for serum cystatin C (CysC) and beta-trace protein (BTP) as markers of renal function in preterm and term neonates.
  
  
  METHODS
  Blood samples of 128 neonates (34% female) admitted to the NICU were analyzed to determine the levels of serum creatinine (enzymatically), CysC and BTP (nephelometric, Siemens Health Care).
  
  
  RESULTS
  The reference intervals, categorized by age, were reported for the 128 neonates. Median (lower/upper limit) BTP were 1.85 (0.57/3.16) and 1.27 (0.51/2.07) mg/L on days 1 and 3. In keeping with maturation of renal function after birth, CysC and BTP fell from days one to day three after birth, whereas creatinine did not.
  
  
  CONCLUSIONS
  Our data provides reference intervals for the levels of creatinine, CysC, and BTP in neonates on days 1 and 3 after birth and demonstrates that CysC and BTP reflect neonatal renal function, whereas creatinine reflects maternal renal function.
authors.affiliation: Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada K1H 8L1.
authors.forename: Erika
authors.initials: E
authors.lastname: Bariciak
authors.affiliation: Department of Pediatrics, Schulich School of Medicine & Dentistry, London, ON, Canada N6A 5W9.
authors.forename: Abeer
authors.initials: A
authors.lastname: Yasin
authors.affiliation: Department of Pediatrics, University of Ottawa, Ottawa, ON, Canada K1H 8L1.
authors.forename: JoAnn
authors.initials: J
authors.lastname: Harrold
authors.affiliation: Ottawa Hospital General Campus, University of Ottawa, ON, Canada K1H 8L6.
authors.forename: Mark
authors.initials: M
authors.lastname: Walker
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8L1.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lepage
authors.affiliation: Department of Pediatrics, Schulich School of Medicine & Dentistry, London, ON, Canada N6A 5W9; Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada N5A 5A5. Electronic address: guido.filler@lhsc.on.ca.
authors.forename: Guido
authors.initials: G
authors.lastname: Filler
mesh_terms: D017677:Age Distribution; D003404:Creatinine; D055316:Cystatin C / Q000097:blood* / Q000592:standards; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D019746:Intramolecular Oxidoreductases / Q000097:blood* / Q000592:standards; D054834:Lipocalins / Q000097:blood* / Q000592:standards; D008297:Male; D012016:Reference Values
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D054834:Lipocalins; D003404:Creatinine; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase