Question

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

a) Antigens in a tissue sample
b) Antibodies in a serum sample
c) Enzymes in a blood sample
d) Lipids in a cell sample

Answer 1

In a direct fluorescent antibody test, a fluorescently-labeled mAb is used to detect specific antigens, particularly bacteria, in a patient sample for rapid diagnosis of diseases like strep throat.

Step-by-step explanation:

In a direct fluorescent antibody (DFA) test, we use a fluorescently-labeled monoclonal antibody (mAb) to detect the presence of specific antigens in a sample. This type of test is particularly useful for the rapid diagnosis of bacterial diseases. For instance, if we are testing for Streptococcus pyogenes which causes strep throat, the label on the mAb will fluoresce under a microscope when it has successfully bound to its target antigen in the throat swab. DFA therefore offers a quick and reliable way to visualize bacteria directly from patient samples, which are otherwise difficult to isolate or culture.