Abstract: Objective To evaluate the clinical value of combined detection of serum rheumatoid factor (RF), anti- cyclic citrullinated peptide antibody (anti-CCP）and 14-3-3η protein in the diagnosis of rheumatoid arthritis (RA)． Methods A total of 94 RA patients were selected as RA group, and 40 healthy people with age, sex matched were used as control group. Serum 14-3-3η protein and anti-CCP were analyzed by enzyme linked immunosorbent assay (ELISA). RF levels were measured by scattering immune turbidimetry. Series and parallel tests were carried out respectively with the above 3 indexes. The sensitivity, specificity, positive predictive value, negative predictive value, accuracy and Youden’ s index (YI) were used to analyze the diagnostic efficacy of each test for RA. Results Among anti-CCP, RF and 14-3-3η protein, anti-CCP showed the highest accuracy (87.4%), YI (0.753) and the highest sensitivity (84.0%), therefore， it was the best measure of RA diagnosis. When using two serum makers, anti-CCP together with RF were an ideal combination with the highest accuracy (87.4%), YI (0.742) and the highest sensitivity (90.4%). While using three serum markers, [(14-3-3η + anti-CCP) / RF], [(14-3-3η + RF) / anti-CCP], [(14-3-3η / RF) + anti-CCP] and [(14-3-3η+anti-CCP) / (14-3-3η+ RF) / (anti-CCP + RF)] showed the higher accuracy (87.4%, 87.9%, 87.4%, 87.9%) and YI (0.745, 0.756, 0.757, 0.760). [(14-3- 3η + anti-CCP) / RF], [(14-3-3η + RF) / anti-CCP] and [(14-3-3η+anti-CCP) / (14-3-3η+ RF) / (anti-CCP + RF)] were the higher sensitivity (88.3%, 89.4%, 87.2%) than [(14-3-3η / RF) + anti-CCP] (81.9%), which was an ideal combination. Conclusion Among anti-CCP, RF and 14-3-3η protein, anti-CCP has the highest accuracy, YI has the highest sensitivity. The combination detection [(14-3-3η + anti-CCP) / RF], [(14-3-3η + RF) / anti-CCP] and [(14-3-3η+anti- CCP) / (14-3-3η+ RF) / (anti-CCP + RF)] has higher accuracy and higher YI, along with good sensitivity.

Key words:  arthritis, rheumatoid, rheumatoid factor, sensitivity and specificity, 14-3-3&eta, protein, anti-cyclic citrullinated peptide antibody