Clinical immunology is performed at the request of the patient. Antitoxins may be used to treat illnesses like diphtheria and tetanus, where the main pathology is caused by certain toxic by-products of the infections. Passive vaccination still has a position in the medical management of several bacterial and viral illnesses, although having been largely supplanted by therapy with antimicrobial medicines. These days, the majority of clinical immunology's focus is on the diagnosis and management of autoimmune illnesses as well as immunology-based medicines used to treat immune-mediated disorders. Patients with inflammatory disorders like rheumatoid arthritis have been proven to benefit from antibodies to several cytokines, such as tumor necrosis factor-alpha. There is hope for the treatment of autoimmune illnesses with other cytokine inhibitors. Antibodies are now used for a variety of purposes more than just diagnosing infectious illnesses. The widespread use of blood transfusion and organ transplantation in medicine and surgery is made possible by the availability of specific immunologic reagents to cell surface alloantigens of erythrocytes or leukocytes. All areas of the contemporary diagnostic laboratory use immunoassays. Strong antibodies are necessary for the hormone assays used in pregnancy tests, which are the most sensitive. Specific antibodies are used in a large number of immunoassays for enzymes crucial to clinical chemistry and haematology. The availability of monoclonal antibodies made from hybridomas has transformed the immunoassay for these uses and expanded its use in several fields of science outside of medicine.