Complement fixation test

Complement fixation test is a serological test used to detect the presence of specific antibodies or antigens in a patient's blood serum. The test was first developed in the early 20th century and has since been used in the diagnosis of a variety of infectious diseases.

History

The complement fixation test was first developed by Jules Bordet and Octave Gengou in 1901. They discovered that the complement system, a part of the immune system, could be used to detect the presence of specific antibodies in the blood serum. This discovery led to the development of the complement fixation test, which has since been used in the diagnosis of a variety of infectious diseases.

Principle

The principle of the complement fixation test is based on the ability of the complement system to lyse red blood cells in the presence of specific antibodies and antigens. If the patient's blood serum contains antibodies against a specific antigen, the complement system will be activated and will lyse the red blood cells. This lysis can be detected by observing the change in color of the test solution.

Procedure

The procedure for the complement fixation test involves several steps. First, the patient's blood serum is mixed with a specific antigen. If the serum contains antibodies against this antigen, they will bind to the antigen and activate the complement system. Next, red blood cells and hemolysin (an antibody that can lyse red blood cells) are added to the mixture. If the complement system has been activated, it will lyse the red blood cells, causing a change in color of the test solution. If the complement system has not been activated, the red blood cells will not be lysed and the color of the test solution will remain unchanged.

Applications

The complement fixation test has been used in the diagnosis of a variety of infectious diseases, including syphilis, measles, mumps, and influenza. It has also been used in the detection of antibodies against certain parasites, such as Trypanosoma cruzi, the causative agent of Chagas disease.

Limitations

While the complement fixation test is a valuable tool in the diagnosis of infectious diseases, it has several limitations. The test is not specific for any one disease, and a positive result can be caused by a variety of different antibodies. In addition, the test requires a high level of technical skill to perform and interpret, and is not suitable for use in routine clinical laboratories.

See also

• Serology
• Antibody
• Antigen
• Complement system