NEW TECHNOLOGIES FOR ANTI-DSDNA ANTIBODIES DETECTION: THERE IS STILL NEED OF HARMONIZATION
- Maria Infantino, Italy
Abstract
Background and Aims
Anti-double stranded DNA antibodies (anti-dsDNA) are considered a specific marker for SLE. Although the Farr technique has been considered the “gold standard” for their detection, currently it has been replaced by numerous newly developed assays. However, there is still no solid evidence of the equivalence of these methods in terms of diagnostic accuracy and of their correlation with the Crithidia luciliae immunofluorescence test (CLIFT).
Methods
Anti-dsDNA antibody levels were measured in 60 patients suffering from different connective tissue diseases, and in 20 diseased controls using four different immunoassays (fluorescence enzyme immunoassay, microdot array, chemiluminescent immunoassay, multiplex flow immunoassay) and by two CLIFT methods.
Results
Average agreement among methods for positive/negative results assessed by the Cohen’s Kappa was 0.71, ranging from moderate to almost perfect (0.53-0.92) (Table1).
Conclusions
Despite good individual performance, new technologies for anti-dsDNA antibody detection are not fully comparable. In particular, their different correlation with CLIFT influences their positioning in the diagnostic algorithm for SLE (either in association or sequentially). Considering the high inter-method variability, harmonization of anti-dsDNA antibody testing remains an unachieved goal.