Abstract: Objective To analyze the effect of red blood cell（RBC） washing procedureon direct antiglobulin test (DAT)by Microcolumn Gel Card, so as to improve the accuracy and reliability ofGel-DAT. Methods 78 Gel-DAT positive samples without washingwas detected by Gel again after three timeswashing. According tothe above experimental results, 78 samples were divided into group A (with changes after washing: the agglutination strength was±~3+), group B (with changes after washing: becamenegative) and group C (with no changes after washing). Group A andB were washed with room temperature normal saline (NS) for five times, then detected with Gelfor DAT. Group C was washed with 37℃ NS for five times, then Gel was incubated at 37℃ for 15 minutes for DAT.We recorded the Gel scoreson each time. Results RBC washing procedure had an effect on DAT Results 4 samples became negative, 3 samplesshowed no change before and after washing, and 71 samplesshowed more scores of agglutination strength after washing. In group A, it was a trend that agglutination intensity wasstrongest afterthe third time washing. In group C,there was no significant change after washing with 37℃ NS, but DAT became negative after incubation Gel on 37℃ for 15 minutes. Conclusion RBC washing procedure has an effect on Gel-DAT. It is suggested that patients' RBC samples should be washedbefore Gel-DAT.According to the clinical diagnosis and the specimen appearance, we select the corresponding washing frequencyand washing temperature, so as to improve the accuracy and reliability of experimental results.

Key words: Direct antiglobulin test, Microcolumn gel card, Erythrocyte washing procedure