In a direct fluorescent antibody test, which of the following would we most likely be looking for using a fluorescently-labeled mAb?

bacteria in a patient sample

bacteria isolated from a patient and grown on agar plates

antiserum from a patient smeared onto a glass slide

antiserum from a patient that had bound to antigen-coated beads

bacteria in a patient sample

Explanation:

Direct fluorescent antibody tests (DFA test) -

In the DFA test, fluorescently labeled mAb is used to bind and to illuminate the target antigen. This tests are use for the quick diagnosis of bacterial disease.

For example, fluorescence - labeled antibodies against the Streptococcus pyogenes is used for the diagnosis of the strep throat from a throat swab.