|
Advantages |
Disadvantages |
| Direct ELISA |
- Simple protocol, time-saving, and reagents-saving.
- No cross-reactivity from secondary antibody.
|
- High background.
- No signal amplification, since only a primary antibody is used and a secondary antibody is not needed.
- Low flexibility, since the primary antibody must be labeled.
|
| Indirect ELISA |
- Signal amplification, since one or more secondary antibodies can be used to bind to the primary antibody.
- High flexibility, since the same secondary antibody can be used for various primary antibodies.
|
- Complex protocol compared with direct ELISA.
- Cross-reactivity from secondary antibody.
|
| Sandwich ELISA |
- High flexibility.
- High sensitivity.
- High specificity, since different antibodies bind to the same antigen for detection.
|
- The antigen of interest must be large enough so that two different antibodies can bind to it at different epitopes.
- It’s sometimes difficult to find two different antibodies that recognize different epitopes on the antigen of interest and cooperate well in a sandwich format.
|
| Competitive ELISA |
- High flexibility.
- High sensitivity.
- Best for the detection of small antigens, even when they are present in low concentrations.
|
- Relatively complex protocol.
- Needs the use of inhibitor antigen.
|
