White Cell Indices and CRP: Predictors of Meningitis in Neonatal Sepsis?

Background Objective: To evaluate the utility of specific cut-off values for C- reactive protein (CRP) and immature-to-total neutrophil ratio (I/T) as screening tests for meningitis in culture negative early onset sepsis (EOS). Materials and Methods Retrospective chart review of 97 newborns with culture negative sepsis who had lumbar puncture performed as part of the sepsis evaluation in a level IIIB NICU at an academic medical center serving a predominantly minority population. Meningitis was defined as either a positive cerebrospinal fluid (CSF) culture or CSF WBC count ≥30/mm. The outcome measures were the sensitivity, specificity and predictive values of CRP >40 mg/L and I/T ratio >0.3 for diagnosing meningitis in newborns with EOS. Results The sensitivity, specificity and positive predictive value of I/T ratio >0.3, CRP >40 mg/L or a combination of these two either at 12 or 24 hours of life were very poor. However, CRP >40 mg/L alone or in combination with I/T ratio >0.3 at both 12 and 24 hours of life had negative predictive values of 85-90%. Conclusion CRP >40 mg/L and/or I/T ratio >0.3 have poor sensitivity, specificity and predictive values as screening tests for meningitis in culture negative early onset sepsis.