A serological test is a laboratory assay. It is used to measure the presence and concentration of antibodies in the blood. It is used to diagnose and monitor several infectious diseases. The antibody molecule is an essential protein. It is produced by the body in response to an infection. The presence of antibodies can then be detected by a serological test. Serological testing is particularly helpful in the diagnosis of certain bacterial, parasitic, and viral diseases. It is also useful in the detection of auto antibodies (harmful antibodies that attack components of the body) that are involved in autoimmune diseases, such as rheumatoid arthritis. Serological testing has proved valuable in the detection of diseases such as syphilis, HIV/AIDS, and epidemic and pandemic infectious diseases (e.g., influenza and coronavirus disease). In ZHC these test are performed on Immuno chromatographic technique and on automated analyzers.