[The analysis to data from Chinese Rheumatism Data Center external quality assurance program for autoantibodies in...

To evaluate the data obtained from the external quality assurance program initiated by Chinese Rheumatism Data Center (CRDC-QAP) for autoantibodies detection in 2021, so as to assess the consensus and differences in cross-laboratory testing to autoantibodies in China. This is a retrospective study. After collecting data from the first half year (from May 15th to July 10th) and the second half year (from August 15th to November 19th) of CRDC-QAP program for autoantibody detection in 2021, it firstly analyzed the qualitative consensus of the cross-laboratory results. Secondly, it compared the positivity grade of numeric results according to the Sample to cut-off ratio (S/CO ratio) calculation. Finally, the mean and coefficient variation (CV) of numeric results from three major manufacturers were calculated. A total of 303 and 332 clinical labs voluntarily participated in the first half year and the second half year of CRDC-QAP program for autoantibody detection in 2021, respectively. Except for anti-β2 glycoprotein type I (aβ2-GPI) IgM, the cross-laboratory consensus of qualitative results for the other autoantibodies is greater than 96%. As for anti-cyclic citrullinated peptide antibody (anti-CCP) and anti mitochondrial antibody-M2 (AMA-M2), the numeric results from more than 90% laboratories showed the same positivity grade. More than 50% of laboratories used chemiluminescence immunoassay (CLIA) for quantitative evaluation of autoantibody. The CV of numeric results from different manufacturers showed certain differences(P<0.01) with the range from 0 to 238%. Although high consensus can be observed in term of qualitative result for autoantibody detection in cross-laboratory, there are still certain differences in numeric results in term of positivity grade and manufacturer-based CV.