Question

What is ELISA and its types?

Answer 1

ELISA :

1. Enzyme-linked immunosorbent assay or ELISA is carried out to detect and measure antibodies, hormones, peptides, and proteins in the blood.
2. ELISA helps to examine the presence of antibodies in the body, in the case of certain infectious diseases.
3. ELISA yields quantitative results and separation of non-specific and specific interactions that take place through serial binding to solid surfaces, which is normally a polystyrene multiwell plate.

Types of ELISA:

Direct ELISA:

1. It uses only one type and it is less time-consuming.
2. The antigen is immobilized to the surface of the multi-well plate and detected with an antibody specific to the antigen.

Indirect ELISA:

1. Indirect ELISA detects the presence of an antibody in a sample.
2. The antigen is attached to the wells of the microtitre plate.
3. A sample containing the antibodies is added to the antigen-coated wells for binding with the antigen.
4. The method can also be used to detect specific antibodies in a serum sample.

Sandwich ELISA:

1. Sandwich ELISA helps to detect the presence of antigen in a sample.
2. It is the most commonly used format.

Competitive ELISA:

1. It helps to detect antigen concentration in a sample.
2. It measures the concentration of an antigen by detecting signal interference.
3. Each of the previous formats can be adapted to the competitive format.