ELISA (enzyme-linked immunosorbent assay) is an essential diagnostic tool used to monitor and maintain health by detecting specific antibodies in a patient's blood serum.
The list below shows five key stages in performing an indirect ELISA test to screen for an infection:
- A: Enzyme-labeled secondary antibodies are added and bind specifically to the patient's primary antibodies.
- B: The well is washed thoroughly to remove any unbound enzyme-labeled antibodies.
- C: The specific antigen of the pathogen is immobilized on the surface of the well.
- D: A specific substrate is added, which is converted by the enzyme to produce a visible color change.
- E: The patient's blood serum is added, allowing any primary antibodies present to bind to the antigen.
Write these stages in the correct order in the boxes below. The first one has been done for you.
C\begin{array}{|c|c|c|c|c|} \hline \mathbf{C} & \quad & \quad & \quad & \quad \\ \hline \end{array}C