Sandwich ELISA
Sandwich ELISAs typically require the use of matched antibody pairs, where each antibody is specific for a different, non-overlapping part (epitope) of the antigen molecule. A first antibody (known as capture antibody) is coated to the wells. The sample solution is then added to the well. A second antibody (known as detection antibody) follows this step in order to measure the concentration of the sample. This type of ELISA has the following advantages:
High specificity: the antigen/analyte is specifically captured and detected
Suitable for complex (or crude/impure) samples: the antigen does not require purification prior to measurement
Flexibility and sensitivity: both direct or indirect detection methods can be used