C-reactive protein - as an early diagnostic marker of early onset sepsis and its correlation with blood culture
Rajesh Kumar, Anupama Deka, S.N.Choudhury, Mainak Roy
Objective: To document effects of intrapartum risk factors for early onset sepsis (EOS) on C-reactive protein (CRP) levels in neonates, and to assess the suitability of this test in diagnosing EOS and its correlation with blood culture in a tertiary care centre. Design: Prospective cohort study. Setting: Labour room and post natal wards in a tertiary level teaching hospital in India. Subjects: 298 neonates at risk of developing infection. Methods: CRP levels in cord blood and neonatal blood at 24 hrs & 48 hrs were estimated. Babies were observed for signs of sepsis for at least 48 hours. If any newborn developed signs of sepsis or sepsis screen done at birth was positive, blood culture was sent and antibiotics was started. Results: 20(6.7%) babies had elevated CRP level in cord blood. At 24 hrs, this elevation was seen in 170(57%) babies while at 48 hrs 100(33.6%) babies showed positive results. Elevated cord CRP levels was significantly associated with rupture of membrane (ROM) >24 hrs, prolonged labour >12 hrs, and maternal fever (p=<0.05). At 24 hours, elevated CRP levels were associated with primiparity, ROM >18hrs, maternal fever, more than three vaginal examinations after membrane rupture, and meconium staining of amniotic fluid (p =<0.05). Fifteen (5.03%) babies developed EOS. The negative predictive value for elevated CRP levels at 24 hrs was 99.2%. Sepsis screen parameters that was significantly associated with proven sepsis were neutropenia <1500/cmm (p=0.01) and immature to total neutrophil ratio (I/T ratio) > 0.2 (p=0.04). Conclusion: Several intrapartum risk factors for early onset sepsis can cause elevation in CRP levels. However, this test may be useful in excluding infection.