Complement fixation test
In the complement fixation test (CFT ) is a test for the detection of antibodies ( Ab) in the blood serum of human and animal patients.
Principle
This results in:
- Serum with spec. Ak → Education of Ak -Ag complexes → complement is consumed → complement can no hemolysis trigger → Ak - positive serum is
- Serum without spec. Ak → Ak no -Ag complexes → complement yet available, leading to hemolysis → → Ak - negative serum
Application
Detection of Ab against: In human medicine:
- Brucellosis pathogen
- Listeriosis pathogen
- Coxsackievirus
- Influenza Virus
- Coxiella burnetii
- Treponema pallidum
- Mycoplasma infections
In veterinary medicine:
- Brucella abortus / melitensis, ovis suis and
- Burkholderia mallei ( glanders )
- Mycoplasma mycoides subspecies ( CBPP )
- Trypanosoma brucei equiperdum ( dourine )
- Leishmania donovani / infantum
Preliminary
Taking place end reactions
He is antigen (Ag ) of the pathogen to be detected against the Ak in the serum and also still complement ( which is obtained from guinea pig serum ) was added.
From the sheep red blood cells and the anti- sheep erythrocyte Ak a complex is formed ( the sheep erythrocytes act as Ag). In the case of the patient's infection, the complement is already consumed and the sheep erythrocytes by the fact that no complement attaches to the anti- sheep erythrocyte Ak - sheep erythrocyte complex, not resolved (ie no hemolysis) → the test is positive, since Ak were present. In the negative case is still complement is available, which attaches itself to the complex with the sheep red blood cells and ensures that the Ak do his work and can dissolve the red blood cells ( hemolysis → ).
- An immunochemical test method
- The diagnostic method in internal medicine