An immunofluorescence test on cell cultures (e.g. HEp-2 cells) identifies nuclear antigenic systems. However, this method often also detects unspecific stimulated nuclear antibodies (e.g. in case of an infection). It is thus necessary to carry out a second test for individual antibodies (ELISA or blot) to verify and confirm the results.
As a standard for routine diagnosis, parallel tests should be carried out on both tissue sections and HEp-2 cells, since some antibodies react differently in each of these systems.