Organizing screening of irregular antibodies in donors from the point of ensuring blood transfusion safety and economic feasibility.

We studied the prevalence of irregular antibodies in blood donors of the Republican Blood Center of Tatarstan in 2021–2023. Antibodies were detected in 135 (0.30%) of 45,042 examined donors. Features of the prevalence of antibodies: 1) in first-time donors it was 0.22% higher than in repeat donors (p<0.001); 2) in women it was 0.24% higher than in men (p<0.001). 27.7% of antibodies were identified, the frequency of identification in women and men does not differ. The detected antibodies are directed against 8 red blood cell antigens, including 79% of antibodies against Rh system antigens. The absence of antibodies to the KEL1 antigen can be explained by the long-term practice of refusing to issue K-positive red blood cells for transfusion. Due to positive autocontrol, 19.2% of antibodies were not identified. Positive autocontrol is 16.3% more common in women. Of the 20 (58.5%) donors invited for repeated examination, a repeated positive result was obtained in 5 (25%) donors. When improving the regulatory framework, it is proposed to quantitatively determine: characteristics of positive control for irregular antibodies, differentiation of clinically significant and insignificant antibodies, use of a direct antiglobulin test.