EA rosette formation: a simple means to increase sensitivity of the antiglobulin test in patients with anti red cell antibodies.

Erythrocyte antibody (EA) rosette formation with the Fc-receptor on the K-562 erythro-myeloid cell line was employed for the detection of subagglutinating amounts of Ig molecules bound to red cells. The sensitivity of this method exceeds that of the conventional direct and indirect antiglobulin tests without any alteration of the incubation media or pretreatment of red cells. The increased sensitivity did not diminish the specificity of the test, which can detect IgG, IgM and complement as well. This method may demonstrate the presence of antibodies on red cells in patients with suspected autoimmune haemolytic anaemia and negative antiglobulin test.