Reference Intervals of Hematological Parameters Among Healthy Newborns in Eastern Sudan: A Hospital-Based Cross-Sectional Study

Background: Accurate interpretation of neonatal complete blood count (CBC) parameters is vital for managing life-threatening conditions in newborns. However, clinical decisions in Eastern Sudan frequently rely on non-local Western-derived or manufacturer-provided reference intervals (RIs), thereby risking diagnostic errors. Therefore, this study aimed to establish the local neonatal hematological RIs for healthy, term newborns in Eastern Sudan. Methods: This hospital-based, cross-sectional study was conducted at New Halfa Hospital. Umbilical cord blood samples were collected from 250 healthy term singleton neonates born to mothers with uncomplicated pregnancies and deliveries. Samples were analyzed using a Sysmex KX-21 hematology analyzer (Sysmex, Kobe, Japan). In accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines, sex-specific 95% RIs were initially estimated, followed by assessment of whether sex-specific partitioning was warranted by calculating the central 2.5th and 97.5th percentiles. Differences in the distributions of hematological parameters between males and females were evaluated using the Mann–Whitney U test. Results: Of the total 250 newborns (123 males, 127 females), no statistically significant differences were found between male and female newborns for any of the eleven evaluated hematological parameters, justifying the pooling of data to establish unified RIs. The established 95% pooled RIs and medians were as follows: white blood cell (WBC) count: 6.33–20.90 × 103/µL (median: 11.15 × 103/µL); red blood cell (RBC) count: 2.91–5.04 × 106/µL (median: 4.02 × 106/µL); hemoglobin: 11.20–16.52 g/dL (median: 13.90 g/dL); hematocrit: 36.30–55.30% (median: 43.70%); mean cell volume (MCV): 93.41–127.53 fL (median: 109.70 fL); platelets: 49.20–438.68 × 103/µL (median: 251.00 × 103/µL); mean platelet volume (MPV): 7.36–11.55 fL (median: 9.30 fL); platelet distribution width (PDW): 16.10–19.37% (median: 16.90%). Conclusions: The results of this study provide preliminary locally derived neonatal CBC RIs for Eastern Sudan. The absence of statistically significant sex differences in this sample supports consideration of pooled neonatal RIs. The lower reference boundaries for hemoglobin, leukocytes, and platelets identified here differ markedly from Western-derived values and those reported in high-altitude cohorts, underscoring the critical clinical need to use these population-specific intervals, which may reduce inappropriate classification arising from the use of non-local reference intervals.