Serology is the study of serum which is the fluid and separate from solute composition of the blood. It is explained as the blood plasma but without fibrinogens, i.e., the clotting factors. When people are exposed to viruses or bacteria, their immune system generates particular antibodies against the organism.
Antibody levels help physicians decide if an infection appeared recently or some time ago. Serology is used in many diagnostic tests to determine blood type.
In addition, viral infections, bacterial infections, and others can be diagnosed with the help of serological studies. Diagnostic tests such as ELISA, CLIA, agglutination, precipitation, etc., are done for detecting antibodies and antigens in the serum.