👉 In biology, "serologically" refers to the process of collecting and analyzing blood samples for the purpose of identifying infectious agents (such as bacteria, viruses, parasites, or fungi) present in a sample. This is done using specialized equipment that can detect specific antigens on the surface of the blood cells. For example, it might be used to determine whether a person has an infection by identifying which antibodies they have produced against a particular pathogen. The blood samples are collected from the patient's bloodstream