A positive test result for ACPA has the greatest specificity for RA and is detectable in patients prior to and in the early stages of disease onset. Some studies have demonstrated that ACPA are present in patients much earlier than RF.
Although many patients have a seropositive test result for RF, this is the case in fewer than 40% of patients in the early course of the disease. Moreover, not only is a positive test result for RF associated with only other autoimmune diseases, infections, connective diseases, but it also occurs in approximately 1%-5% of healthy patients.
Although anemia of chronic disease is a common laboratory finding among patients with RA, it also occurs in and correlates with disease activity of other chronic conditions, including other autoimmune diseases, kidney disease, infection, and cancer.
As with RF and anemia of chronic disease, ANA are associated with other chronic conditions. In addition, although approximately 40% of patients with RA have a positive test result for ANA, most test results of nuclear antigen subsets are found to be negative.
Learn more about laboratory studies in the workup of patients in whom RA is suspected.
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Herbert S. Diamond. Fast Five Quiz: Rheumatoid Arthritis Workup - Medscape - Jun 10, 2020.
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