Diagnostic Role of Complete Blood Count (CBC) and C-reactive Protein (CRP) in Suspected Early-Onset Sepsis and Antibiotic Stewardship in the Neonatal Intensive Care Unit (NICU).

BACKGROUND: Early-onset sepsis (EOS) is a major cause of neonatal morbidity and mortality, but its diagnosis remains challenging because early clinical manifestations are nonspecific and blood culture results are not immediately available. Consequently, many neonates receive empirical antibiotics despite subsequently having negative blood cultures, increasing unnecessary antibiotic exposure and prolonging neonatal intensive care unit (NICU) stay. Readily available laboratory markers such as complete blood count (CBC) parameters and C-reactive protein (CRP) are commonly used to support clinical decision-making; however, neither marker alone is sufficiently accurate to confirm or exclude EOS. OBJECTIVE: This study evaluated the diagnostic utility of CBC parameters and CRP in neonates with suspected EOS and assessed their potential role in supporting antibiotic stewardship decisions. METHODS: This single-center retrospective observational study was conducted over one year in a NICU. Preterm and term neonates with EOS risk factors and National Neonatology Forum sepsis scores ≥10 were included, started on empirical antibiotics after blood culture collection, and monitored clinically. CBC parameters, CRP, and blood culture results were analyzed. Neonates with positive blood cultures were classified as culture-positive EOS, while those with negative cultures were classified as culture-negative suspected EOS. RESULTS: Among 573 NICU admissions, 94 neonates (16.4%) had suspected EOS, of whom 22 (23.4%) were culture-positive, and 72 (76.6%) were culture-negative. Leukopenia (WBC <5,000/mm3), a higher neutrophil percentage (>50%), thrombocytopenia, and elevated CRP were significantly associated with culture-positive EOS (p < 0.05). Gram-negative organisms predominated among culture-positive isolates (73%). Culture-negative suspected EOS accounted for most suspected cases and was associated with a longer NICU stay. CONCLUSION: CBC parameters and CRP are useful adjuncts in evaluating suspected EOS when interpreted with blood culture results and clinical stability. These laboratory findings may inform antibiotic stewardship protocols, although their effect on antibiotic discontinuation requires prospective evaluation. Antibiotic decisions should be guided by clinical status, culture findings, serial laboratory trends, and local microbiological patterns.