Red cell distribution width as a diagnostic and prognostic biomarker in neonatal sepsis: A scoping review

Background Neonatal sepsis remains a leading cause of infant mortality worldwide, with the greatest burden in low- and middle-income settings. Diagnosis is largely clinical and supported by blood culture, despite being limited by delayed results and suboptimal sensitivity. Red cell distribution width (RDW), a routine parameter in the full blood count, has been explored as a simple and cost-neutral marker of systemic inflammation and sepsis. Methods We conducted a scoping review of published research in MEDLINE, EMBASE, Scopus, and the Cochrane Library from inception to December 2025, supplemented by manual screening of reference lists. Studies evaluating RDW as a diagnostic and/or prognostic marker in neonates (≤28 days) with suspected or confirmed sepsis were included. Results Fourteen studies involving 2907 participants were included in this review. RDW levels were significantly higher in septic neonates compared to healthy controls, with diagnostic accuracy with Area Under Curve (AUC) ranging from 0.70 to 0.97. Elevated RDW served as a strong independent predictor of mortality, with prognostic AUCs between 0.75 and 0.80; thresholds above 19–20% correlated with an increased risk of mortality. In comparison to CRP and ESR, RDW often matched or exceeded their diagnostic performance. However, significant methodological heterogeneity exists regarding laboratory standards, timing of sampling, and sepsis definitions. Conclusions RDW is a promising and accessible marker for early risk stratification, particularly in resource-limited settings. However, current evidence is insufficient to support its use as a standalone tool; therefore, further studies are needed to validate its role in the future clinical settings.