To remember this type of ELISA, imagine a sandwich! The antigen is the filling and the antibodies ar

To remember this type of ELISA, imagine a sandwich! The antigen is the filling and the antibodies are the yummy bread. Hungry, aren’t you?

In this type of ELISA, an antibody of a particular antigen is adsorbed to the walls of well.

Then sample antigens are added.

If the sample contains desired antigen it will bind to the antibody.

After the unbound antigens are washed off, detection antibodies which bind specifically to desired antigen are added.

Unbound detection antibodies are washed off followed by substrate addition.

Sample containing bound detection antibody will give colour change indicating the presence of  antigen and the sample which do not have any bound detection antibody will be colourless.