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Updated: May 20, 2026
Anti-Nuclear Antibody Screening Using HEp-2 Cells
Published on: June 23, 2014
Diagnostic value of anti-Sa and anticitrullinated protein antibodies in rheumatoid arthritis
Yan-Feng Hou1, Guang-Zhi Sun, Hong-Sheng Sun
1Department of Radiology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China.
Objective:
To determine the diagnostic value of anticitrullinated protein antibodies, second generation (ACPA2), by electrochemiluminescent immunoassay (ECLIA) and anti-Sa by ELISA in a large cohort of Chinese patients with early rheumatoid arthritis (RA).
Methods:
One hundred ninety-eight patients with early RA (< 1 yr duration), 112 with other rheumatic diseases, and 60 healthy individuals were studied.
Results:
The combination of anti-Sa and ACPA2 positivity had the highest specificity (99.42%), but it had a rather low sensitivity (50.0%). The combination of anti-rheumatoid factor (RF) and ACPA2 showed the highest sensitivity (80.30%), with specificity of 95.93%. The mean titer of ACPA2 and RF was significantly higher in the anti-Sa-positive group compared to the negative group (ACPA2, p <0.001; RF, p = 0.007). The 28-joint Disease Activity Scores of the anti-Sa-positive patients were significantly higher than those of the negative group (p = 0.01). The anti-Sa had no significant correlation with age, sex, antinuclear antibody, SSA, SSB, erythrocyte sedimentation rate, C-reactive protein, immunoglobulin A (IgA), IgG, IgM, C3, and C4.
Conclusion:
Our results come from a newly developed ECLIA for detection of ACPA2 and the anti-Sa-antibody-based ELISA system. The combined application of ACPA2 and anti-Sa tests can improve the laboratory diagnosis of early RA.
