| Assay Type | Description | Applications |
|---|---|---|
| Double antibody sandwich (DAS) ELISA | Also called direct ELISA. An antibody specific to the antigen is immobilized on a surface. The sample containing the antigen is added, followed by a labeled secondary antibody that also recognizes the antigen. This forms a “sandwich” of capture antibody-antigen-detection antibodies. [Image] | Detection of specific antigens in a sample |
| Triple antibody sandwich (TAS) ELISA | It is also called indirect ELISA and is often used to identify antibodies in patient blood that may be there as the result of infection. [Image] | Detection of low-abundance antigens, mainly for a diagnostic test for diseases such as HBV |
| Competitive ELISA | The antigen or antibody of interest in the sample competes with a labeled version for binding to a limited amount of immobilized antibody or antigen. The detection is based on the competition between the natural unlabelled antigen to be tested for a labeled form of the antigen which is the detection reagent. [Image] | Detection of specific antigens or antibodies. Mainly used when the antigen is small and has only one epitope |
| Dissociation enhanced Lanthanide Fluorescence immunoassay (DELFIA) | A time-resolved fluorescence immunoassay that uses lanthanide chelate antibody labels to generate a fluorescent signal when stimulated with the light of a specific wavelength. The light signal generated has a long decay which enhances the negative to the positive ration of the assay. | Detection of specific antigens or antibodies, particularly in complex or autofluorescent samples |
Reference:
- Principles and Techniques of Biochemistry and Molecular Biology by John Walker, Keith Wilson.