Introduction: Early diagnosis and management of neonatal sepsis plays an important role in determining patient outcomes. The Immature to Total Neutrophil Ratio (IT ratio) is one of the diagnostic criteria for neonatal sepsis. However, the IT ratio examination is separate from the complete blood examination, and must be carried out manually or with an automatic microscope. The systemic immune-inflammation index (SII) is calculated by multiplying the number of platelets by the number of neutrophils and dividing by the number of lymphocytes derived from the complete blood count (CBC) examination. Recent studies have shown that SII values increase significantly at the time of diagnosis of neonatal sepsis. This study aims to find the correlation between the IT ratio and SII in septic neonates.
Methods: This cross-sectional analytical observational study was conducted at the Wangaya Regional General Hospital, Denpasar. Data was taken from medical records of patients admitted from June 2022 to September 2023. Neonates with major congenital abnormalities, autoimmune diseases, immunodeficiency conditions and incomplete medical record data were excluded from the study. The correlation between the SII value and the IT ratio was analyzed using the Pearson correlation test. Data analysis was carried out using the SPSS version 25 software.
Results: This study consisted of 31 septic neonates who met the inclusion and exclusion criteria. Most of the subjects in this study were male and preterm neonates. The median IT ratio and SII were 0.20 and 875.92 x103/ul respectively. The correlation value or r value between SII and the IT ratio was 0.386 with a P value of 0.060.
Conclusion: Increased SII in septic neonates occurs due to thrombocytosis and neutrophilia as a response to systemic inflammation. Meanwhile, lymphocyte activation is inhibited which causes a decrease in immune function. Although no correlation between the IT ratio and SII was observed, further diagnostic research needs to be carried out to analyze the ability of SII to diagnose neonatal sepsis.