Usually, autoantibodies are detected by searching for fluorescent antinuclear antibody (FANA). Lab technicians may use other approaches, such as the enzyme-linked immunosorbent assay (ELISA), but the gold standard approach is immunofluorescence microscopy. In this procedure, the laboratory takes a slide coated with fixed, permeable cells (purchased from a manufacturer) and applies it to the slide of the patient’s serum. The serum is allowed to incubate and cleaned off afterward.
At this point, they will be bound to the slide if the patient has antinuclear antibodies. Of course, it can’t be seen, but a second fluorescent tag antibody (also purchased from a manufacturer) is then added to the slide, allowed to incubate, and washed off. These antibodies can now fluoresce under the microscope if the patient has antinuclear antibodies that are attached to the cells on the slide.
This test is cool because it can tell not only whether there are antibodies (by seeing green things on the nuclei of the cells), but also what kind of antibodies they might be (by seeing the kind of positive pattern present).
