Abstract: A method of forward blood grouping is presented wherein known antibodies are attached to a solid surface and the red blood cells presented for immunological reaction are activated with a proteolytic enzyme. A reverse blood grouping procedure utilizes synthetic or purified antigens which are attached directly to a solid surface. The surface is then contacted with an unknown blood component to permit antibodies to undergo immunological reaction with the previously attached antigens. A solution of red blood cells is used as the indicator. A method of performing a major crossmatch utilizes anti-human immunoglobulin that is attached to a solid surface which is then contacted by the two blood components to permit an antigen-antibody interaction of red blood cells and antibodies. The antibody sensitized cells will immunologically adhere to the solid phase.