For those not familiar, many if not all of the larger commercial labs have switched theier ANA testing to ELISA systems. In my expereince there is a difference between the older IFA (immunofluoresce) testing and ELISA– some patients are positive only on one of the assays. I could see how ELISA might be more reproducible, but I would still favor IFA. The future will likely be all ELISA.
About Alan Matsumoto, M.D.
Part-time Faculty, Division of Rheumatology
Johns Hopkins University