Answer:
bacteria in a patient sample
Step-by-step 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 .