The principle of the antibody screening test is to react the tested serum with special reagent red blood cells, that is, screening red blood cells, to discover reactive antibodies at 37°C. The methods used in the test include immediate centrifugal saline test method, low ionic strength medium method (Liss), enzyme test method, antiglobulin test, etc., which can be selected according to the serological behavior of the antibody and the specific conditions of the test, but the antibody must be tested. Globulin test.