A new reliable test for crossmatching: microplate hydrogel immunoassay technology

SUMMARY Objectives To provide a novel assay to detect incomplete antibodies in the crossmatching test. Background There is a requirement in China that both major and minor crossmatch tests are required. Among all methods of crossmatching, the tube anti‐human globulin test requires tedious washing steps and is time‐consuming, whereas the microcolumn gel immunoassay anti‐human globulin test is susceptible to sample quality. Methods The process of the microplate hydrogel immunoassay anti‐human globulin test involves the use of our patented hydrogel chromatography medium and U‐bottom microplates pre‐coated with goat anti‐human globulin (AHG). A mixture of red blood cells (RBCs) and serum is centrifuged through the hydrogel under precise conditions. In incompatible reactions, the sensitised RBCs are captured by the pre‐coated AHG and form a layer over the bottom of the well, whereas in compatible reactions, the unbound RBCs form a button at the bottom of the well. The sensitivity of this new approach and the performance when testing old specimens were evaluated. Results This approach was more convenient and slightly more sensitive than the tube anti‐human globulin test and was superior to the microcolumn gel immunoassay when testing old specimens. Conclusion In general, this assay is suitable for the routine clinical use of crossmatching to detect incomplete antibodies.