Which lab tests are used to differentiate rheumatoid arthritis (RA) from osteoarthritis (OA)?

Updated: Jun 10, 2020
  • Author: Carlos J Lozada, MD; Chief Editor: Herbert S Diamond, MD  more...
  • Print
Answer

Rheumatoid arthritis is associated with prominent, prolonged (>1 hour) morning stiffness and overtly swollen, warm joints. Radiographic findings include bone erosion (eg, periarticular osteopenia or marginal erosions of bone) rather than formation. Laboratory findings that further differentiate rheumatoid arthritis from osteoarthritis include the following:

  • Systemic inflammation (elevated erythrocyte sedimentation rate [ESR] or C-reactive protein [CRP] level)

  • Positive serologies (rheumatoid factor [RF] or anti–cyclic citrullinated peptide [anti-CCP] antibodies)

  • Inflammatory joint fluid with a predominance of polymorphonuclear leukocytes (PMNs)

  • Elevated white blood cell (WBC) count


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!