Direct immunofluorescence assay (DFA)

Definition

Direct immunofluorescence assay (DFA) is a laboratory technique used to detect specific antigens in tissue samples by employing fluorescently-labeled antibodies. It allows for the visualization of antigen-antibody complexes under a fluorescence microscope.

5 Must Know Facts For Your Next Test

1. DFA utilizes fluorescent dyes conjugated to antibodies to target specific antigens.
2. The technique requires a fluorescence microscope to observe results.
3. DFA is commonly used for diagnosing infections, autoimmune diseases, and other conditions involving specific proteins.
4. It provides direct evidence of the presence of an antigen in a sample.
5. Preparation and fixation of the sample are crucial steps in ensuring accurate results.

Review Questions

• What type of microscope is required to observe the results of a DFA?
• In what contexts is DFA typically used?
• Why is proper sample preparation important in DFA?

Related terms

Fluorescence Microscope: A type of microscope that uses fluorescence instead of, or in addition to, reflection and absorption techniques.

Antibody: A protein produced by the immune system that binds specifically to an antigen.

Antigen: A substance that induces an immune response, often targeted by antibodies.