OBJECTIVES: The objectives of this study were to evaluate and compare the ratio of erythrocyte concentrates with low hemoglobin concentrations among voluntary male and female blood donors. Then look into the relationship between low hemoglobin levels and previous donor rejections. STUDY DESIGN: The analysis was conducted as a cross-sectional research study using historical data from the Osijek Clinical Hospital Center's Clinical Institute for Transfusion Medicine. MATERIALS AND METHODS: Data was collected from the national program for Transfusion Service of the Republic of Croatia e-Delphyn and from quality control laboratory. The CompoLab machine was used to determine the hemoglobin concentration in the donor's capillary blood. Erythrocyte concentrates were produced in line with the guidelines for the centrifugation and separation process. The equipment used to determine hemoglobin concentrations from the dose was Mindray BC-3600. Descriptive statistics were used to analyze the data. RESULTS: Male donors provided 80 % of the blood samples, while female donors provided 20 %. The percentage of erythrocyte concentrates with reduced hemoglobin is 7 %, out of which 84 % are non-compliant erythrocyte concentrates from female donors. Statistics show that female doses are statistically more non-compliant than male doses. Among the non-compliant doses, 53 % of donors were previously declined. CONCLUSION: Among donors with a normal concentration of hemoglobin from the capillary blood sample, 7 % of the doses do not meet the hemoglobin criteria. Female donors are much more likely than male donors to administer non-compliant doses. Although it is not statistically significant, female donors that do not fulfill the requirements for hemoglobin in the dose, are rejected more than that of male donors.