Direct fluorescent antibody (DFA) tests

Definition

Direct fluorescent antibody (DFA) tests use fluorescent-labeled antibodies to directly detect the presence of specific antigens in a sample. They are commonly used in microbiology to identify pathogens quickly and accurately.

5 Must Know Facts For Your Next Test

1. DFA tests involve the use of antibodies labeled with a fluorescent dye that binds directly to the target antigen.
2. These tests are highly specific, as they rely on antigen-antibody binding for detection.
3. DFA tests can provide rapid results, often within hours, which is crucial for timely diagnosis and treatment.
4. They are commonly used to diagnose infections caused by bacteria, viruses, and fungi.
5. The fluorescence can be observed under a fluorescence microscope, allowing for visual confirmation of the presence of the pathogen.

Review Questions

• What type of label is used in DFA tests?
• How do DFA tests achieve their high specificity?
• What kind of infections can DFA tests help diagnose?

Related terms

Indirect Fluorescent Antibody (IFA) Tests: Tests where the primary antibody binds to the target antigen and a secondary fluorescent-labeled antibody binds to the primary antibody.

Fluorescence Microscope: A specialized microscope used to observe specimens that fluoresce under ultraviolet light.

Antigen-Antibody Binding: The specific interaction between an antigen and an antibody that allows for targeted detection in immunological assays.