Serology

Serological tests are diagnostic methods that are used to identify antibodies or antigens in a patient's sample. Serological tests may be performed to diagnose infections or autoimmune illnesses, to check if a person has immunity to certain diseases, and in many other situations, such as determining an individual's blood type. Several methods can be used to detect antibodies and antigens, including ELISA, False negative results for antibody testing can occur in people who are immunosuppressed, as they produce lower amounts of antibodies, and in people who receive antimicrobial drugs early in the course of the infection. Transfusion medicine Blood typing is typically performed using serologic methods. The antigens on a person's red blood cells, which determine their blood type, are identified using reagents that contain antibodies, called antisera. When the antibodies bind to red blood cells that express the corresponding antigen, they cause red blood cells to clump together (agglutinate), which can be identified visually. The person's blood group antibodies can also be identified by adding plasma to cells that express the corresponding antigen and observing the agglutination reactions. Other serologic methods used in transfusion medicine include crossmatching and the direct and indirect antiglobulin tests. Crossmatching is performed before a blood transfusion to ensure that the donor blood is compatible. It involves adding the recipient's plasma to the donor blood cells and observing for agglutination reactions. The indirect antiglobulin test is used to screen for antibodies that could cause transfusion reactions and identify certain blood group antigens. . Immunology Serologic tests can help to diagnose autoimmune disorders by identifying abnormal antibodies directed against a person's own tissues (autoantibodies).. Several autoantibodies are used as clinical biomarkers to diagnose a autoimmune disease or in differential diagnosis of autoimmune diseases. Also in atopic allergy diseases diagnosis the allergen specific IgE level is measured by a serologic assay. == Serological surveys ==

A 2016 research paper by Metcalf et al., amongst whom were Neil Ferguson and Jeremy Farrar, stated that serological surveys are often used by epidemiologists to determine the prevalence of a disease in a population. Such surveys are sometimes performed by random, anonymous sampling from samples taken for other medical tests or to assess the prevalence of antibodies of a specific organism or protective titre of antibodies in a population. Serological surveys are usually used to quantify the proportion of people or animals in a population positive for a specific antibody or the titre or concentrations of an antibody. These surveys are potentially the most direct and informative technique available to infer the dynamics of a population's susceptibility and level of immunity. The authors proposed a World Serology Bank (or serum bank) and foresaw "associated major methodological developments in serological testing, study design, and quantitative analysis, which could drive a step change in our understanding and optimum control of infectious diseases." In a helpful reply entitled "Opportunities and challenges of a World Serum Bank", de Lusignan and Correa observed that the In another helpful reply on the World Serum Bank, the Australian researcher Karen Coates declared that: In April 2020, Justin Trudeau formed the COVID-19 Immunity Task Force, whose mandate is to carry out a serological survey in a scheme hatched in the midst of the COVID-19 pandemic. == See also ==