Known as the “wear and tear” arthritis, osteoarthritis (OA) is the most common form of arthritis, affecting over 30 million Americans.5
Many symptoms of OA and RA overlap, including pain, swelling, and stiffness in the joints. These similarities can cause difficulty when differentiating the diseases. Differential diagnosis of OA and RA is important because treatments differ.6
Depending on the joint, classification criteria may include joint symptoms (pain, stiffness, swelling, enlargement, deformation), age, erythrocyte sedimentation rate, radiologic findings (presence of osteophytes or narrowing of joint space), synovial fluid tests (color, appearance, white blood cell count), and the sensation of crackling in the joint (crepitus).7
In addition, some laboratory markers are elevated in RA patients but normal in OA patients. A positive or elevated result for rheumatoid factor or cyclic citrullinated peptide antibody may suggest inflammatory arthritis, such as RA, rather than OA.