Serological examination is mainly a method to check the concentration of various antibodies or substances in the serum by immunological means. There are various items of serological examination, the common ones are: First, the examination of various serum immunoglobulins, including immunoglobulin G, immunoglobulin A, immunoglobulin D, immunoglobulin E, immunoglobulin M, and also the examination of various serum complements. Second, the commonly used test is the examination of various viral antibodies, including hepatitis C virus antibody, HIV antibody, syphilis antibody test. The five tests for hepatitis B, including hepatitis B surface antigen, hepatitis B surface antibody, core antibody, hepatitis B e antigen, and hepatitis B e antibody tests. There are also various serological tests including various tumor markers, such as fetoprotein, carcinoembryonic antigen, etc.