Laser incubation for the rapid detection of red cell alloantibodies in human blood samples

Background and Objectives: Pre-transfusion antibody screening requires the detection and identification of immunoglobulin G (IgG) antibodies against red blood cells (RBCs). Using the indirect antiglobulin test (IAT), plasma–RBC solutions are incubated at 37°C in gel cards, typically by heating block technology. Here, we apply the newly developed laser incubation method to detect RBC alloantibodies in the plasma from human donors. Materials and Methods: Donated human plasma samples (N = 128) containing clinically significant IgG antibodies directed against Rh (D, C, c, C^w and E), Kell (K and Kp^a), Duffy (Fy^a and Fy^b), Kidd (Jk^a) and MNS (S) blood group system antigens were tested by the indirect antiglobulin test (IAT). Samples were heated to 37°C by infrared laser (980 nm) for incubations of up to 5 min. Samples were also incubated in a heating block for comparison. Results: When heating by laser, the presence of an alloantibody is detected after only a 1-min incubation for 96% of samples. No samples required longer than 3 min of laser incubation in order to detect the antibody. For all samples, incubation by laser gave the same or stronger result within 5 min. No samples required longer than 5 min to achieve an equivalent result to that of the 5-min heating block incubation. The laser was not found to damage cells or antibodies. Conclusion: Laser incubation provides comparable results in shorter time frames than the heating block. Laser incubation can rapidly detect even very weak antibodies.