Background: Blood count is the most commonly prescribed biological examination in general medical practice. The reference intervals of the hematological parameters of this examination are critical for clinical orientations and therapeutic decisions. Because there are racial, ethnic, and geographical differences in complete blood count (CBC) reference intervals (RIs), population-specific RIs must be established. The goals of this study were to identify hematological reference ranges in healthy adult Eritreans. Method: 942 healthy Eritreans between 18 and 60 years old were included,331 males and 611 females by use of a DXH500 analyzer, age ranging between 18-60 years. The venous blood sample was collected in a tube containing EDTA anticoagulant for the blood tests. SPSS version 25 statistical software was used for data analysis, P value < 0.05 was considered significant A non-parametric test was used for the determination of upper (97.5th percentile) and lower (2.5th percentile) reference interval limits with 95% CI. The Harris and Boyd Rule is used to determine the need for partitioning reference intervals based on gender. Results: The established 95% reference intervals combined median (2.5th–97.5th percentile) for both males and females were: WBCs: 6.37  (3.02-13.55x103/µL), Lymph%:39.34 (21.39-60.54 %), Mono %:8.98 (5.18-14.54%), Neut%: 49.13(16.90-81.98 %),  Baso%: 0.22 (0.00-0.63%),  MCV: 87.67 (76.58-97.29fl), MCH: 27.53 (20.46-32.70 pg), MCHC: 31.38 (25.20-35.30 g/dl, RDW: 14.65 (12.70-18.60 %), PLT: 286.83 (131.62-453.13 x103/µL) and MPV: 8.92 (7.28-11.01fl). The parameters that demand separate RI and Their respective median (2.5th – 97.5th percentile) for males versus females were: Eosin: 3.86 (0.29-16.68 %) versus 1.80 (0.20-6.73 %), RBCs: 5.57 (4.47-7.69x106/µL) versus 4.97 (3.98-6.38x106/µL), Hb: 15.28 (11.48-17.99 g/dl) versus 13.50 (10.74-16.54 g/dl), and HCT: 48.75 (38.96-61.17 %) versus 43.19 (34.86-58.60 %). The median of WBCs was significantly higher in females than males, the mean WBCs were lower in people residing at high altitudes compared to those leaving at low altitudes, The WBC is significantly higher among obese participants. The median Platelet count is significantly higher in females than in males. Conclusion: The reference intervals established in this study differ from the international one and thus should be used for the interpretation of laboratory results in diagnosis and follow-up in Eritrea. The study showed significant variations in Hb levels, RBCs count, WBCs count, and platelet according to gender, Age, BMI, and physical activity.

The authors have declared no competing interest.

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The Eritrean Ministry of Health's ethics committee granted ethical approval for this study.

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