What is the difference between direct and indirect immunoassays?

Direct and indirect immunoassays are laboratory techniques used to detect and measure antigens or antibodies. The main difference between them is the method of detection:

Direct Immunoassay:

1. Labelled antibody: A labelled antibody (e.g., enzyme, fluorescent, or radioactive) is directly bound to the antigen.
2. One-step reaction: The labelled antibody reacts with the antigen in a single step.
3. Quick and simple: Fast and straightforward procedure.