Biomarkers for early diagnosis of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the joints and can even lead to disability. No treatment can completely cure RA, and early intervention is the most effective way to improve the prognosis. Autoantibodies are important in disease diagnosis, treatment, and prognosis assessment, especially rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs), which have been widely used in clinical practice. Several studies have fully discussed the critical roles of RF and ACPA in the pathophysiology of RA, but fewer reviews focus on advances in RF and ACPA-related assays for early diagnosis. Therefore, this article outlines the clinical applications and predictive value of RF and ACPA in early RA diagnosis, along with emerging immunoassays published in the last five years. Additionally, it discusses the advantages and challenges of multiplex immunoassay techniques for simultaneous RF and ACPA detection. Finally, some suggestions for improving the performance of combined testing were summarized to achieve early diagnosis of RA, thereby delaying disease progression.