Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 56 9 2018 12 25 571 576 EN Leili Koochakzadeh Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Mirgholamreza Mahbod Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran. Reza Pakzad Department of Epidemiology, School of Health, Ilam University of Medical Sciences, Ilam, Iran. Davood Jafari Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Fahimeh Khoshhal Department of Nursing, Dezful University of Medical Sciences, Dezful, Iran. Abbasali Yekta Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran. Mehdi Khabazkhoob Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2018 01 24 2018 11 05 Measurement of hematological parameters and their reference ranges play an important role in the diagnosis and treatment of many infectious diseases and cancers. However, there are marked differences in the reference ranges between developing and developed countries. The aim of this study was to establish reference ranges of hematological parameters. This cross-sectional study was conducted in patients visiting Noor Eye Hospital who had no systemic diseases. In the lying position, blood samples were collected in two test tubes (Becton Dickinson Ltd, UK) using the Venoject method. EDTA-containing blood samples were used for complete blood count and differential leukocyte count using a cell counter (Nihdon Kohden Celltac E, Japan). Descriptive statistics, t-test, and ANOVA were used for data analysis. The data of 46,595 individuals were analyzed of whom 47.3% (n=22,042) were men. The mean (95% confidence interval) of white blood cells (WBC), red blood cells (RBC), platelet, and Hemoglobin (Hb) was 6.68 (6.66-6.69), 4.83 (4.83-4.84), 238.40 (237.87-238.93), and 14.29 (14.27-14.30), respectively. There was no difference in hematological parameters between male and female subjects. Except for the platelet count that was higher in individuals below 18 years than those 18-64 years and ≥65 years, other parameters had no relationship with age. Normal values of hematological parameters in the Iranian population are similar to the Middle East and African countries but below standard reference values. Except for the platelet count that decreased with age, there was no significant difference in hematologic and immunologic parameters between age and sex groups. Considering the difference between our results and standard reference values, we suggest that normal values be determined locally for each country. https://acta.tums.ac.ir/index.php/acta/article/view/6987 https://acta.tums.ac.ir/index.php/acta/article/download/6987/5155