A comparison of ELISA assays as routine diagnostic test for detection of autoantibodies against extractable nuclear antigens

Objective: In an analytical evaluation, commercially available ELISA test k its for detection of antibodies directed against extractable nuclear antige ns (ENA) were compared with the currently used combination of counterimmuno electrophoresis and immunoblotting. Design: Three screening ELISAs and two typing ELISAs were tested. These met hods 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 rega rd 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 o f reactivity (possibly caused by differences in amount of coated antigen). The other three ELISAs were reliable and sensitive for detection of ENA aut o-antibodies. Conclusions: The ELISA ENA screen assays ENA-LISA(TM) polyvalent and Mileni a ENA screen and typing assays ENA-LISA(TM) are reliable and sensitive for detection of autoantibodies in clinical specimens without substantial false negatives. Copyright (C) 1999 The Canadian Society of Clinical Chemists.