Physical Examination

Physical examination of the joints is one of the primary tests used by doctors to diagnose rheumatoid arthritis. During the physical exam, the doctor will inspect the joints for signs of swelling and tenderness. They will also check the range of motion in the joints and look for signs of stiffness, particularly in the morning or after periods of inactivity. Some key things the doctor may look for include swollen joints, joint pain or tenderness, warmth over the affected joints, and limited range of motion. The joints most commonly affected early on are those in the hands, wrists, elbows, knees and feet.

Blood Tests

Several common blood tests are used to help diagnose rheumatoid arthritis and determine disease activity levels. One important screening blood test is the rheumatoid factor (RF) test. The RF test checks for the presence of antibodies against immunoglobulin G (IgG), which are frequently found in people with RA. However, RF is not entirely specific to RA as it can also be present in people with other autoimmune diseases. A newer blood test called the anti-CCP (anti-cyclic citrullinated peptide) test checks for antibodies against citrullinated proteins and is more specific for RA. Elevated inflammatory markers like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) can also provide clues about RA disease activity levels.

Imaging Tests

Various types of imaging tests are useful for RA diagnosis and monitoring joint damage over time. X-rays are helpful for detecting bone erosions and joint space narrowing characteristic of RA. Magnetic resonance imaging (MRI) can detect earlier signs of inflammation in soft tissues surrounding joints prior to bone damage appearing on x-rays. Ultrasound is a non-invasive imaging method sometimes used to visualize joint inflammation in areas like the wrists and fingers. It can detect fluid accumulation, thickening of synovial membranes and structural changes not seen on standard x-rays.

Synovial Fluid Analysis

When joints are actively inflamed, doctors may perform arthrocentesis to extract and analyze synovial fluid from the joint space. Synovial fluid from RA patients typically shows signs of inflammation like increased white blood cell count and the presence of immune cells like monocytes, macrophages and lymphocytes. The synovial fluid may be tested for crystals in some cases to rule out other causes of arthritis. Analyzing synovial fluid can aid the diagnosis of RA and help determine if infection or another inflammatory condition is present.

Making the Diagnosis

No single test establishes an unequivocal diagnosis of rheumatoid arthritis. The diagnosis involves a careful clinical evaluation including medical history, physical exam findings and confirmation with laboratory/imaging results. The American College of Rheumatology has established classification criteria to standardize the diagnostic process. A definitive diagnosis requires the presence of specific symptoms, clinical signs and abnormal test results. Factors like the number and location of involved joints, presence of autoantibodies and abnormalities on imaging studies all help differentiate RA from other types of arthritis. Treatment is usually not started until RA can be definitively diagnosed based on fulfilling several of the classification criteria.

Prognosis and Monitoring Disease Progress

Once patients are definitively diagnosed with rheumatoid arthritis, doctors will continue monitoring them periodically to gauge disease activity levels and track how well or poorly the condition is responding to treatment. Regular checkups involve repeat physical exams, blood tests, and sometimes imaging to determine if new or additional treatment may be needed. The goals are to catch any worsening of symptoms early before permanent joint damage occurs. Key tests for monitoring include ESR/CRP, RF and anti-CCP levels which generally correlate with RA disease activity levels. Periodic x-rays can evaluate for progression of damage over time. disease modifying therapies aim to control symptoms, reduce inflammation and prevent long-term joint destruction.