LAUSR

OBJECTIVES The diagnostic tests for autoimmune disease include screening for autoantibodies for nuclear antigens (ANA) and antibodies against extractable nuclear antigens (ENA). Using the line immunoassay (LIA) method, various kinds of ENA antibodies can be detected simultaneously. We evaluated the performance of the newly launched LIA-ANA-Profile-17S (Shenzhen YHLO Biotech, Shenzhen, China) as compared to a conventional LIA kit. METHODS Residual samples were collected from 200 patients who had been tested for ANA using indirect immunofluorescence. The LIA-ANA-Profile-17S was compared to the EuroLine ANA (Euroimmun, Oberlausitz, Germany) for the analysis of 17 different autoantibodies. The concordance rate and agreement between assays were determined. Samples showing discrepancies between the LIA-ANA-Profile-17S and EuroLine tests were further examined through additional analysis. RESULTS The overall agreement was moderate (kappa = 0.759, 95% CI = 0.712-0.805). Agreement between assays ranged from weak to almost perfect, except for those tests targeting nucleosomes, histones, and PM-Scl. Of the 57 disparate results between LIA-ANA-Profile-17S and EuroLine, 38 (66.7%) samples tested positive under an additional assay, showing variable patterns between types of autoantibodies. The positive rate of each autoantibody between LIA-ANA-Profile-17S and EuroLine did not differ significantly, except for anti-nucleosome and anti-histone assays in samples from patients diagnosed with systemic lupus erythematosus (P = 0.004 and 0.001, respectively). CONCLUSIONS Compared to those from the conventional EuroLine assay, the LIA-ANA-Profile-17S results showed variable agreement in samples showing different prevalence of each autoantibody. The most frequently detected antibodies showed almost perfect agreement. The LIA-ANA-Profile-17S could play a role in the diagnosis of systemic autoimmune disease in ANA-positive samples.