A recent meta-analysis of three cohort studies where patients with early RA were tested for both RF and ACPA,10 showed that the positive likelihood ratio increased from 22.0 (95% confidence interval [CI] = 9.9 to 49.1) for ACPA alone to 27.1 (95% CI = 10.1 to 72.7) when both ACPA and RF results were positive. The gene discussed is PRTN3; the disease is rheumatoid arthritis.