CLINICAL USEFULNESS OF POLYETHYLENE GLYCOL-USING ANTI-GLOBULIN TEST FOR DETECTION OF RED CELL ANTIBODIES

Compared to the conventional anti-globulin test (AGT), polyethylene glycol (PEG)-using AGT (PEG-AGT) was found to be not only simpler and easier, but also superior with regard to specificity and sensitivity to detect unexpected antibodies. In a basic study for the application of PEG to direct AGT (DAT), it was found that the addition of PEG to red cells from patients followed by incubation for 5 to 20 minutes at 37°C provided the most sensitive results. Of 1082 patients' sera for antibody screening, red cell alloantibodies in 8 and warm-type red cell autoantibody in 1 could be detected by PEG-AGT, but not by AGT. On the other hand, one anti-E IgM antibody, probably in its early stage of production, was detected by Bromelin method, but not by PEG-AGT. In two other patients PEG-AGT demonstrated a positive reaction two months before the onset of autoimmune hemolytic anemia (AIHA), whereas AGT result remained negative. PEG-AGT seemed to be an adequate method specially to detect low-titer IgG antibodies in both DAT and indirect AGT, and it will provide useful indexes for the diagnosis of AIHA and also for the observation of clinical course of patients with such diseases as AIHA.