The association of solid-phase assays to immunofluorescence increases the diagnostic accuracy for ANA screening in patients with autoimmune rheumatic diseases

This study is the first that compares the IIF method vs. solid-phase assays in the detection of ANA, on a very large sample size from the routine work-up (real-life approach). Results show that the association of solid-phase CTD screen tests to the ANA-IIF test increases the sensitivity (from 89.2% to 97.4%) and the specificity (from 64.6% to 98.4%) of serological tests for ANA screening. Analysis of costs demonstrated that combination of the two tests is also cost-effective, reducing global costs for the immunoserological diagnosis of AARD by 22%.