- Direct immunofluorescence test is used to detect unknown antigen in a cell or tissue by employing a known labeled antibody that interacts directly with unknown antigen. If antigen is present, it reacts with labeled antibody and the antibodycoated antigen is observed under UV light of the fluorescencemicroscope Direct immunofluorescence test is widely used for detection of bacteria, parasites, viruses, fungi,or other antigens in CSF, blood, stool, urine, tissues, and other specimens.
- The need for preparation of separate labeled antibody for each pathogen is the major disadvantage of the direct immunofluorescence test.