Hybridoma technology allows for the mass production of monoclonal antibodies. It involves fusing antibody-producing B cells from the spleen of an immunized mouse with myeloma cancer cells, creating a hybridoma cell. These hybridoma cells are selected using HAT medium, which causes them to continuously secrete identical monoclonal antibodies. Monoclonal antibodies have many medical applications, including diagnosing diseases and infections through detection of specific antigens. For example, pregnancy tests detect the HCG hormone using monoclonal antibodies, and HIV tests detect HIV antibodies in blood serum using a multi-step process with monoclonal antibodies.