POSSIBLE METHOD FOR IRREGULAR ANTIBODY SCREENING BY FLOW CYTOMETRY

Abstract

It is very important to perform irregular antibody screening to ensure safe and efficient red blood cell transfusion. In this study, we developed a new method to detect IgG class irregular antibodies by flow cytometry using anti-human IgG as a secondary antibody (Flow Cytometry Irregular Antibody Screening: FCM-SC). The mean fluorescence intensity ratio of the patient sample to negative sample (S/N) was estimated. The result was considered positive if S/N was greater than 1.7. For clinically significant antibodies like anti-E and anti-S, 12 out of 95 cases with Column Agglutination Technology (CAT) positive results were FCM-SC negative, and additional testing by PEG-IAT confirmed the negative results. 22 out of 29 cases that were anti-M and anti-Le^a antibody positive by CAT were FCM-SC negative, and additional testing by IAT without enhancement media revealed that all cases were negative. 9 out of 33 cases that did not show reaction specificity by CAT, such as by autoantibody and cold agglutination, were FCM-SC negative, and additional testing by PEG-IAT using plasma that had been treated with a reducing agent also showed negative results. These results suggest that FCM-SC is a useful method for detecting IgG class irregular antibodies and may be suitable for antibody screening.