Which of the Following is Incorrect Regarding the Complement Fixation

Question

Which of the following is incorrect regarding the complement fixation test?
A)First antigen and antibody are allowed to react.
B)Purified complement proteins are added to the antigen-antibody tube.
C)Sheep red blood cells are added to the antigen-antibody-complement mixture.
D)Hemolysis of the sheep red blood cells occurs in a positive test result.

Accepted Answer

Hemolysis of the sheep red blood cells is not a positive test result in complement fixation test. In fact, hemolysis is prevented by the presence of the complement proteins added to the mixture. A lack of hemolysis is indicative of a positive test result because it indicates that the complement proteins have been used up in the reaction, meaning that the antigen and antibody were present in the original mixture.