Despite the fact that biomarker selection for the test was based on statistical contribution to estimation of disease activity, the MBDA biomarkers represent critical cytokine signaling pathways in RA (IL-6, TNFRI) as well as hallmark RA disease processes, including angiogenesis and tissue remodeling (VEGF-A, EGF), cell recruitment and invasion (VCAM-1), cartilage remodeling (MMPs), and elevated acute-phase response (CRP, SAA). Here, IL6 is linked to rheumatoid arthritis.