Abstract Background/Aims 14-3-3η is a joint-derived soluble biomarker linked to RA pathogenesis and joint damage. Prior studies have demonstrated its diagnostic utility. This study confirms and expands on earlier findings by evaluating the specificity of 14-3-3η in a clinically diverse RA and disease control cohort. Methods Serum 14-3-3η was measured in a total of 615 subjects (50 RA and 545 controls) using the Augurex ELISA. Group differences were assessed using Mann-Whitney and Kruskal-Wallis. ROC area under the curve (AUC) analysis and Fisher’s Exact test evaluated the diagnostic performance of 14-3-3η. 14-3-3η positivity was set at 0.19 ng/ml with statistical significance being p 0.05. Results Median (IQR) serum 14-3-3η levels were significantly higher in established RA 0.94 ng/ml (0.20-14.15) than all controls 0.02 (0.00-0.06), p 0.0001 (Table 1). 14-3-3η’s differential expression yielded a significant AUC of 0.93, p 0.0001, with 76% sensitivity and 93% specificity. 14-3-3η positivity was significantly associated with RA diagnosis (OR = 42.3, 95% CI: 20.4-87.5, p 0.0001). Conclusion This study reinforces the diagnostic value of serum 14-3-3η, demonstrating significantly elevated levels in RA patients compared to a broad spectrum of disease controls. With a high specificity of 93% and a strong association with RA diagnosis (OR = 42.3), 14-3-3η emerges as a robust biomarker that can enhance diagnostic confidence in clinical settings. Disclosure A. Marotta: Shareholder/stock ownership; Augurex Life Sciences Corp. W.P. Maksymowych: Consultancies; Augurex Life Sciences Corp, Abbvie, Eli-Lilly, Novartis, Pfizer, UCB, BMS, Celgene, Galapagos. R. Sengupta: Consultancies; Biogen, Abbvie, Pfizer, BMS, Novartis, UCB. Honoraria; Augurex Life Sciences Corp. S. Bleakley: Corporate appointments; Augurex Life Sciences Corp. S. Wichuk: None. N. Biln: Shareholder/stock ownership; Augurex Life Sciences Corp.
Marotta et al. (2026) studied this question.