Objective To discuss the preschool children after hepatitis B vaccines injected,the variation trend of hepatitis B surface antibody (HBsAb)'s positive rate- Methods 4149 preschool children's HBsAb were examined ,by means of enzyme linked immunosorbent assay(ELISA). Results The HBsAb's positive rate among the age from 0～2,2.1～3.0,3.1～4.0,4. 1～5.0,5.0～6.0,for each age period,children's HBsAb positive rates was 64.65% ,68.64% ,71.55% ,74.21%,68.38% respectively. The statistical analysis showed that there was statistcal significance(x2=19.77, P

Objective To investigate the appropriate cross-matching methods for the direct antiglobulin test (DAT)positive patients.Methods The DAT was used to screen the irregular antibodies on the surface of erythrocytes.The microcolumn gel test was used for blood identification.The antiglobulin test and manual polybrene test were used for cross-matching.Re-sults A total of five DAT positive cases were collected in study.The blood groups of each case were detected,including A-DCcEe,O-DCCee,O-DCcee,A-DCCee and A-DCcee.The donor samples with corresponding blood-antigen negative were cho-sen for cross-matching,and the agglutination intensity of each cross-matching tube was weaker than the control.The transfu-sion of washed red blood cells was suggested.Finally,each transfusion was safe and efficient.Conclusion The infusion of the washed red blood cells with corresponding blood-antigen negative could efficiently ensure the safety of blood transfusion.