Serum (blood) toxic response. Blood is centrifuged to remove cellular components. Anti-coagulated blood yields plasma containing fibrinogen and clotting factors. Coagulated blood (clotted blood) yields serum without fibrinogen, although some clotting factors remain. Serum is an essential factor for the self-renewal of embryonic stem cells in combination with the cytokine leukemia inhibitory factor. The serum of convalescent patients successfully recovering (or already recovered) from an infectious disease can be used as a biopharmaceutical in the treatment of other people with that disease, because the antibodies generated by the successful recovery are potent fighters of the pathogen. Such "convalescent serum" (antiserum) is a
Blood transfusion Blood transfusion Blood transfusion is generally the process of receiving blood or blood products into one's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors, and platelets. Red blood cells contain hemoglobin and increase iron levels by improving the amount of oxygen found in the body. White blood cells, are not commonly used during transfusion but are related to the immune system and to fight infections.