ESR1 and rheumatoid arthritis: There were no significant differences in understanding diagnostic test between RA and PsA participants for ACPA, ESR and CRP (Table 2), however when comparing the female and male participants, all showed higher level of understanding by female participants (Figure 3B andTable 2, CRP 36.4% vs 17.2%, ESR 32.7% vs 14.4%, ACPA 10.5% vs 5.1%).