Non-infectious conditions and gestational age influence C-reactive protein values in newborns during the first 3 days of life

Background: Our aim was to analyze C-reactive protein (CRP) values in term and preterm infants and correlate non-infection-associated increases with various neonatal disorders. Methods: Retrospective cohort study that included all newborns hospitalized at a tertiary care center between 2004 and 2007 with documented CRP values in the first 3 days of life. Analysis of differences in CRP values between term and preterm newborns and cases with CRP increases in sepsis negative newborns. Results: For diagnosis of blood culture proven sepsis (19 and 14 cases, respectively) in 353 preterm and 179 term newborns, CRP at a cut-off of 8 mg/L had sensitivities of 53% and 86% and specificities of 91% and 88%, respectively. The area under the receiver operating characteristics curves were 0.799 and 0.890, respectively. Preterm newborns had lower median values compared to term newborns in sepsis positive (9 vs. 18.5 mg/L, p < 0.001) and negative newborns (0.5 vs. 2 mg/L, p < 0.001). Increases in individuals without infection were correlated significantly with meconium aspiration syndrome and surfactant application in term newborns (p=0.009 and 0.025, respectively) and with surfactant application and higher birth weight in preterm newborns (p < 0.001 and 0.031, respectively). Conclusions: CRP values were significantly lower in preterm compared to term newborns, and its application in the diagnosis of sepsis in preterm newborns was not as reliable as in term newborns. Meconium aspiration syndrome, surfactant application, and high birth weight were associated significantly with increased CRP values.