Best of 2021: Seronegativity in RA studied using sera and microarrays from 559 RA (283 ACPA-) found 9 autoAbs w/ >90% specificity for seroneg RA. anti-PTX3 & anti-DUSP11 had best performance w/ sensitivity 38% & specificity 88% https://t.co/jFAnpQzmve