Abstract: Objective To analyze the distribution of unexpected antibodies of pediatric inpatients and the impact of gender, age, and blood transfusion history on antibody production. Methods Blood samples from 4 345 pediatric inpatients were collected for unexpected antibody screening. Positive samples were further performed antibody identification using panel cells. Positive rate of different types of unexpected antibodies were calculated. Besides, we separated the patients into different groups according to gender (male and female), age (infant, preschool, and school-age) or blood transfusion history. Differences of positive rate of unexpected antibodies between different groups were statistically analyzed. Hence, the influence factors of generating unexpected antibodies were comprehensively analyzed. Result 59 of 4 345 hospitalized patients were found to carry unexpected antibodies, with an overall positive rate of 1.3%. And 53.4% of the antibodies derived from MNS system, mainly anti-M. The second most antibodies was from Rh system which accounted for positive rate of 10.3% with anti-E being in the majority. Antibody of Kidd system was identified in only one sample with the positive rate of 1.7%. 21 cases of other types of antibodies (3 cases of drug antibodies, 9 cases of autoantibodies, and 9 cases of specific unknown antibodies) were identified, accounting for the rate of 36.2%. There was no statistical difference of positive rate between genders (P>0.05). Compared with preschool group (3~6 years old) and school-age group (above 6 years old), positive rate of infant group (0~3 years old) was higher with a statistically significant difference (P<0.05). The positive rate of antibodies from MNS and Kidd systems had no statistical difference between patients with and without blood transfusion history. While, the positive rates of Rh system and other antibodies in patients with blood transfusion histories were significantly higher than those in patients without blood transfusion history (P<0.05). Conclusion The distribution of unexpected antibodies in pediatric inpatients was mainly from MNS and Rh blood group systems. Both age and blood transfusion history were the impact factors to generate unexpected antibodies. Antibodies from MNS system had no correlation with blood transfusion histories, while, the generation of antibodies of Rh system was obviously stimulated by blood transfusion. Hence, it is quite necessary to perform not only ABO/RhD but also RhCcEe consistent tranfusion for patients with a history of blood transfusion or who need repeated long-term blood transfusion during clinic treatment.

Key words: Pediatric inpatients, Unexpected antibodies, Risk factors, History of blood transfusion, Blood transfusion safety