Background: Chorioamnionitis (CHORIO) is a major risk factor for early onset neonatal sepsis (EOS). The Committee on the Fetus and Newborn (COFN) recommends performing CBC and optional CRP in neonates born to mothers with CHORIO. The COFN recommends to discontinue antibiotics at 48-72 hours if infants are asymptomatic and blood culture is negative even if CBC and CRP is abnormal. There is no clear rational for performing CBC/CRP in neonates born to mothers with CHORIO as they are not guiding the therapy. Objective: To determine the utility of performing screening CBC and CRP in neonates born to mothers with CHORIO. Design/Methods: This is a retrospective study on 1033 late-preterm and term infants (≥ 35 weeks gestation) born to mothers with CHORIO between 11/2006 and 6/2015. The data on CBC and CRP performed at 12 hours of age were collected. Abnormal I:T ratio was defined as ≥0.2, abnormal CRP > 1mg/dl. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NNP), negative predictive value (NPV), positive likelihood ratio (LR+) and negative likelihood ratio (LR-) of I:T ratio and CRP for the diagnosis of culture proven sepsis were collected. Results: This study included 1029 infants exposed to CHORIO who had CBC and CRP performed at 12 hours of life. Thirty one percent of neonates had abnormal I:T ratio or CRP at 12 hours of age as depicted in Table 1. Only 4 out of the 1029 neonates (0.4%) born to mothers with CHORIO developed blood culture positive EOS. Abnormal IT ratio and CRP has very poor PPV (1.46% and 1.6%) but excellent NPV (99.9% and 100%). Table 2. Conclusions: CBC and IT ratio have very poor PPV in neonates born to mothers with CHORIO. We agree with the COFN recommendation for not prolonging antibiotics course for abnormal CBC or CRP. IT ratio and CRP at 12 hours of age in neonates exposed to CHORIO have very strong NPV. Experts can consider recommending discontinuing antibiotics at 12-24 hours in neonates exposed to CHORIO.

Table 1

CHORIO-exposed neonates with abnormal I:T ratio and CRP at 12 hours of life

Table 1

CHORIO-exposed neonates with abnormal I:T ratio and CRP at 12 hours of life

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Table 2

Sensitivity, specificity, PPV, NPV of abnormal I:T ratio and CRP for culture proven EOS

Table 2

Sensitivity, specificity, PPV, NPV of abnormal I:T ratio and CRP for culture proven EOS

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