Defining a new cut-off point at three times that established by the manufacturer (60 IU/mL) in order to identify patients with high ACPA titers according to ACR/EULAR 2010 classification criteria for RA, we observed that with this new cut-off point, the specificity of the assay increases considerably, exceeding 90%, and consequently the LR+ is also notably high, which suggests that patients with high levels of ACPA are approximately nine times more likely to have RA than those without high levels (Table 6). The gene discussed is PRTN3; the disease is rheumatoid arthritis.