What is complementary fixation in microbiology?

Complement fixation is a traditional technique used to show whether specific antibodies are present in a patient's serum such as serum or cerebrospinal fluid against a particular pathogen. It primarily focuses on measuring IgG antibodies, allowing researchers to analyze the immune response against the virus. This method works by  introducing a complement into a well-suited combination of these antibodies and antigens. Some diagnostic tests rely on the addition of complements to detect the presence of those particular antibodies or antigens in a sample.