AB1336 COMPARATIVE STUDY OF ANTI-CCP ANTIBODIES BY LATEX ENHANCED TURBIDIMETRIC IMMUNOASSAY AND ELISA
Authors: Yanyao Wu, Xiang-Cong Zhao, Jing Luo
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Some of the autoantibodies found in RA are primarily directed against these citrullinated protein epitopes and can be found even before the symptoms of arthritis appear <sup>[1]</sup>. So the detection of these antibodies can be used in clinical practice to help develop therapeutic strategies. The classic method for detecting anti-CCP antibodies in serum is ELISA. However, the traditional ELISA method still has some inevitable limitations, such as time-consuming, complicated process and low degree of automation, may not be able to provide clinicians with quick answers. Therefore, the purpose of our study was to determine whether the LETIA, which was faster than ELISA, can be used in routine experiments, and to explore the clinical application value of the LETIA in the detection of anti-CCP antibodies. <h3>Objectives:</h3> The purpose of our study was to evaluate the consistency of Latex Enhanced Turbidimetric Immunoassay (LETIA) and ELISA in the detection of anti-cyclic citrullinated peptide antibodies (anti-CCP antibodies) in 139 patients, for the diagnosis of early rheumatoid arthritis (RA), and to determine that LETIA can be used in daily practice. <h3>Methods:</h3> A total of 139 serum or plasma samples were collected from patients with or suspected of having RA. The anti-CCP antibodies of these samples were detected by LETIA and ELISA simultaneously, all tests were carried out in accordance with the manufacturer's standard procedures. Finally, we compared the technical performance and diagnostic accuracy, and assessed the clinical sensitivity and specificity of these two methods. <h3>Results:</h3> The Kappa coefficient and consistency rate measured between LETIA and ELISA were greater than 0.91. The sensitivity and specificity values of LETIA were 83.33% and 95.6%, respectively. The positive predictive value and negative predictive value were 90.91% and 91.58%, respectively. The confidence interval of 95% positive coincidence rate was 78.97-82.75%, while the confidence interval of 95% negative coincidence rate was 92.72%-94.79%. The sensitivity and specificity values of ELISA proposed by the manufacturer for clinical diagnosis RA were 82% and 95%. The two methods had the same detection effect. <h3>Conclusion:</h3> The current commercially available methods for detecting anti-CCP antibodies were roughly the same, and the consistency between LETIA and ELISA were high. In general, the LETIA was more accurate and sensitive than the ELISA in the detection of anti-CCP antibodies in serum. Overall diagnostic performance of ELTIA can be compared. LETIA provided reliable information about antibody levels that made it useful in monitoring disease activity. Comparable to the classic ELISA, ELISA may even be replaced in the future. <h3>References</h3> [1] Harich R, Roger C, Garnier L, et al. Comparison of anti-CCP autoantibodies measurement by ELISA and a bead-based assay in a large patient cohort.[J]. Clinical Biochemistry, 2014, 47(6):485-488. <h3>Disclosure of Interests:</h3> None declared