title: Citrulline concentration in routinely collected neonatal dried blood spots cannot be used to predict necrotising enterocolitis.
abstract: OBJECTIVE
  Low citrulline concentration is a marker of low functional enterocyte mass, which may predispose neonates to necrotising enterocolitis (NEC). We hypothesised that citrulline could be used to assess the NEC risk that could not be accounted for by gestational age and birthweight. This study investigated whether citrulline concentrations routinely measured in neonatal dried blood spots (DBS) could predict NEC.
  
  
  METHODS
  We used national Danish registries to retrospectively identify all 361 babies born between 2003 and 2009 who were diagnosed with NEC and had a valid citrulline concentration measured from a DBS sample. The control group comprised 1083 healthy newborns, with three controls for every newborn with NEC, matched for birthweight and gestational age.
  
  
  RESULTS
  Neonatal dried blood spots were collected between 2 and 21 days of life, with a median of 8 days. The results showed that NEC was not associated with low citrulline concentration, either in a direct comparison between the NEC and control groups or in a multivariate logistic regression (p = 0.73).
  
  
  CONCLUSIONS
  The findings of this study show that the citrulline concentrations found in routine DBS samples between 2003 and 2009 did not predict NEC in newborn babies.
authors.affiliation: Department of Neonatology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Englund
authors.affiliation: Department of Neonatology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: R Á
authors.initials: RÁ
authors.lastname: Rogvi
authors.affiliation: Danish Center for Neonatal Screening, Clinical Mass Spectrometry, Statens Serums Institut, Copenhagen, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Melgaard
authors.affiliation: Department of Neonatology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
authors.forename: G
authors.initials: G
authors.lastname: Greisen
mesh_terms: D002956:Citrulline / Q000097:blood*; D003955:Diagnostic Tests, Routine; D059788:Dried Blood Spot Testing; D020345:Enterocolitis, Necrotizing / Q000097:blood* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies
chemical_list: D002956:Citrulline
keywords: Citrulline; Dried blood spot; Necrotising enterocolitis; Neonatal Screening