A Retrospective Study: The Significance of Combined Testing of Serum Markers for Diagnosis of Rheumatoid Arthritis

Abstract

BackgroundThere have been few studies on the value of various antibody combinations in rheumatoid arthritis (RA) diagnosis, and a lack of studies with large sample sizes, especially in the Chinese population. This study retrospectively evaluated the diagnostic value of a combined assay of five auto-antibodies [anti-cyclic citrullinated peptide (anti-CCP), anti-keratin (AKA), anti-RA 33, glucose-6-phosphate isomerase (GPI), and rheumatoid factor (RF)] for RA.Material/MethodsData were obtained from 5,725 patients with rheumatic diseases in Southwest Hospital of Chongqing from 2011 to 2014. Detection of the five serological markers was performed for all study patients using the appropriate method for each antibody.ResultsIt was found that of the 5,725 patients, the positive rates for RF, anti-CCP, anti-RA 33, AKA, and GPI were 52.5%, 40.1%, 12.8%, 12.0%, and 50.0% respectively. In RA patients, the positive rates were 83.3%, 68.5%, 16.6%, 20.8%, and 77.9% respectively, which were all significantly higher than those detected in patients with the other diseases (p<0.01). The areas under the receiver operator characteristic (ROC) curve for RF, anti-CCP, anti-RA 33, AKA, and GPI were 0.857, 0.831, 0.528, 0.602, and 0.822 respectively, indicating that these five serological markers display favorable diagnostic value for RA. There were positive correlations between anti-CCP antibody and RF and GPI (p<0.01) and between RF and GPI (p<0.01), but no correlation between anti-RA 33 and AKA (p<0.01). The specificity of the combination of anti-CCP, AKA, and GPI was 100% for RA diagnosis.ConclusionsThe combined assay of serological markers significantly improved the diagnostic specificity for RA. The diagnostic value of RF for RA was the highest and the combined assay for anti-CCP, AKA, and GPI had the highest specificity for RA diagnosis.

Diagnostic accuracy of anti-keratin antibody for rheumatoid arthritis: a meta-analysis

“…To demonstrate excellent accuracy, the value of AUC should be more than 0.97, and AUC of 0.75-0.92 is considered to be good [43]. AUC value was 0.7194 in this study implied that AKA had a moderate diagnostic accuracy, and it was higher than in previous study [25].…”

“…They finally named it anti-keratin antibody (AKA) [22]. In previous studies, it was found that a specificity of AKA was from 79 to 100% in the diagnosis of RA [23,24], whereas its sensitivity ranged from 20 to 80% [25,26]. Therefore, in order to determine whether AKA can be used as an auxiliary diagnostic serum marker for RA, we carried out this meta-analysis.…”

Diagnostic value of anti-cyclic citrullinated peptide antibody combined with rheumatoid factor in rheumatoid arthritis in Asia: a meta-analysis

“…After excluding this study, the AUC, sensitivity, and specificity were 0.84, 0.86, and 0.73, respectively. In the series analysis, influence evaluation ( Figure 8D ) and outlier detection ( Figure 8D ) found three studies 43 – 45 that might influence the robustness of the conclusions. After omitting the three studies, the AUC, sensitivity, and specificity were 0.90, 0.64, and 0.96, respectively.…”

“…Based on the strict inclusion and exclusion criteria, 24 published papers were included in this meta-analysis, 22–45 including 21 combined in series and 8 combined in parallel. In total, 7151 cases of RA and 5913 controls were included.…”