Evaluation of systemic inflammatory response index parameters in newborns born at ≥35 weeks of gestation and admitted to the neonatal intensive care unit

Evaluation of systemic inflammatory response index parameters in newborns born at ≥35 weeks of gestation and admitted to the neonatal intensive care unit AIM: Neonatal sepsis and transient tachypnea of the newborn (TTN) are among the leading causes of neonatal intensive care unit (NICU) admission in infants born at ≥35 weeks of gestation. The nonspecific clinical features of sepsis and the delay in obtaining laboratory confirmation create significant challenges for early diagnosis. Systemic inflammatory indices derived from complete blood count parameters have been proposed as supportive biomarkers; however, their diagnostic utility in late-preterm and term newborns remains uncertain. For this reason, this study was conducted to evaluate systemic inflammatory index parameters in clinical sepsis, suspected sepsis, and TTN groups and to investigate their potential contribution to early diagnostic assessment. MATERIALS AND METHODS: This prospective study was carried out in a tertiary-level NICU between 01 December 2024 and 01 October 2025. A total of 173 newborns who met the inclusion criteria were categorized into three groups: clinical sepsis, suspected sepsis, and TTN. Demographic, clinical, and laboratory data were systematically recorded. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), systemic inflammatory response index (SIRI), and pan-immune-inflammation value (PIV) were calculated from complete blood count parameters. In the second phase of the study, hematological measurements obtained on the first and seventh days were compared. Statistical analyses were performed using nonparametric methods. RESULTS: Systemic inflammatory indices alone were not found to be sufficient for confirming sepsis; however, low SIRI values appeared to support the exclusion of infection in suspected cases. The similarity of index levels between clinical sepsis and TTN indicated that non-infectious perinatal factors may influence these inflammatory parameters. CRP demonstrated the highest diagnostic performance among the biomarkers evaluated. The combined use of systemic inflammatory indices with conventional inflammatory markers was considered potentially beneficial for diagnostic interpretation and for supporting clinical follow-up during the treatment process. Keywords: Neonatal sepsis, systemic inflammatory index, transient tachypnea of the newborn