Evaluation of the automated indirect immunofluorescence test for anti-dsDNA antibodies

Abstract Background Anti-dsDNA antibodyis a specific antibody in systemic lupus erythematosus (SLE). Indirect immunofluorescence test (IIFT) is a highly specific method in detecting anti-dsDNA antibody. The application of automated system has gained better consistency than manual operation. This study detected anti-dsDNA antibodiesusing EUROPattern Computer-aided immunofluorescence microscopy (EPA), and evaluated the performance of the automated system. Methods The sera of 96 patients with suspected SLE and 102 control patients were examined using IIFT. The consistency between the EPA and manual reading was analyzed. Results Analysis of 198 samples showed that the overall consistency of the negative/positive results between the EPA and manual reading was 94.95%. Based on the manual reading results, the sensitivity and specificity of EPA were 95.70% and 94.29%, respectively. The analysis of 57 samples with non-specific fluorescence showed that the overall consistency of the negative/positive results was 96.49%. The analysis of the antibody titerof 89 positive samples showed that the consistency between the EPA and manual reading was 97.75%. Conclusion EPA was consistent with the manual reading with regard to qualitative reading and antibody titer. With low-exposure function, EPA could read samples with non-specific fluorescence. EPA was superior to manual reading in automation and standardization.