Fast Five Quiz: Joint Pain

Herbert S. Diamond, MD


February 12, 2019

Potentially useful laboratory studies in suspected RA fall into 3 categories (markers of inflammation, hematologic parameters, and immunologic parameters), and include the following:

  • Erythrocyte sedimentation rate (ESR)

  • CRP level

  • Complete blood count

  • RF assay

  • Antinuclear antibody assay

  • Anti−cyclic citrullinated peptide and anti−mutated citrullinated vimentin assays (currently used in the 2010 American College of Rheumatology [ACR]/European League Against Rheumatism [EULAR] classification criteria)

ESR and CRP levels are associated with disease activity. The CRP value over time correlates with radiographic progression.

Routine viral screening by serologic testing does not significantly facilitate the diagnosis of RA in patients with early RA, nor is it helpful as a potential identifier of disease progression.

RF is not specific for RA, but is also present in other connective tissue diseases, infections, and autoimmune disorders, as well as in 1% to 5% of healthy people. The presence of RF predicts radiographic progression of bone erosions, independent of disease activity.

Ultrasonography of joints is gaining increased widespread acceptance in clinical practice; however, its use in RA is not yet the standard of care. Radiography remains the first choice for imaging in RA: it is inexpensive, readily available, and easily reproducible, and it allows easy serial comparison for assessment of disease progression.

Read more about the workup of RA.


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