A rheumatoid factor test can detect the presence of rheumatoid factor, an antibody that may mistakenly attack healthy cells and tissues. The body may produce RF as a result of an abnormal immune ...

Multivariable adjusted hazard ratios rose from 3.6 (95% confidence interval, 1.7 - 7.3) for RF levels of 25 to 50 IU/mL to 6.0 (95% confidence interval, 3.4 - 10) for 50.1 to 100 IU/mL and to 26 ...

Smoking remains a major risk factor for nodule development, along with long-standing, severe RA, male sex, and seropositivity for rheumatoid factor or anti-cyclic citrullinated peptide antibodies.