Objective: In an analytical evaluation, commercially available ELISA test kits for detection of antibodies directed against extractable nuclear antigens (ENA) were compared with the currently used combination of counterimmunoelectrophoresis and immunoblotting.
Design: Three screening ELISAs and two typing ELISAs were tested. These methods were fairly simple, easy to perform and "user friendly," because most of the reagents were ready to use.
Results: The agreement with the current methods was good, but the screening as well as typing ELISAs proved to be more sensitive, especially with regard to detection of SS-A auto-antibodies. The cut-off range of one screening assay was not well established and one typing assay suffered from problems with inaccuracy of package insert, purity of antigen and standardisation of reactivity (possibly caused by differences in amount of coated antigen). The other three ELISAs were reliable and sensitive for detection of ENA auto-antibodies.
Conclusions: The ELISA ENA screen assays ENA-LISA polyvalent and Milenia ENA screen and typing assays ENA-LISA are reliable and sensitive for detection of autoantibodies in clinical specimens without substantial false negatives.