Abstract: Objective To observe the antibody prevalence of Toxoplasma gondii in blood donors and analyze the residual risk of blood transfusion in Tangshan City. Methods A total of 308,024 blood samples were tested for IgG and IgM antibodies to T. gondii. The distribution characteristics, risk factors and residual risk of blood transfusion were analyzed. Results There were 3 453 cases （1.14%） of blood donors who were found to be positive for Toxoplasma antibodies, and the frequency trends to be increasing （from 0.92% in 2013 to 1.30% in 2018） （χ²=32.449, P<0.05）; the positive rates were high in those with undercooked meat consumption, frequent contact to animals and repetitive blood donations（3.78%, 2.85% and 2.14%, respectively）. The total risk of Toxoplasma transfusion residue in the blood donors was 9.39×10^-6, and that in those with raw/undercooked food consumption （37.33×10^-6） was high （5.57×10^-6）. The risk of blood transfusion residue in those with frequent contact to animals （40.06×10^-6） and repeated donations （14.30×10^-6） was elevated compared with the other donors （P<0.05）. Conclusion The antibody prevalence of Toxoplasma gondii in blood donors seems to be increasing. The high risk of T. gondii residue in blood donors with raw/undercooked foods and/or frequent contact to animals may be a potential threat to blood safety .

Key words: Blood donation, Toxoplasma infection, Risk of residual blood transfusion