Rheumatoid Arthritis

Condition that causes hot, red, swelling (inflammation) and pain of the joints, normally hands and feet are affected first and then the rest (e.g. elbows, wrist, knees, ankles).

• Over time they can be permanently damaged.
• It can cause inflammation of tear glands, salivary glands, heart and lungs and blood vessels.

Diagnosis Tests

To diagnose arthritis a range of diagnostic tools need to be used.

Example of blood test results include:

• Red blood cell count (RBC): Long term inflammation can cause a low red blood cell count.
• White blood cell count (WBC): An elevated white blood cell count suggests the possibility of an active infection. Patients taking corticosteroids (for inflammation) may have an elevated WBC due to the medication.
• Hemoglobin and hematocrit: Low hemoglobin and hematocrit may be indicative of anaemia (anaemia can be associated with rheumatoid arthritis) and/or other long term diseases or possible bleeding caused by medications
  • Non-steroidal anti-inflammatory drugs (NASIDS)
  • Corticosteroids
• Platelet count: The platelet count is often high in rheumatoid arthritis patients, while some potent/strong arthritis medications can cause platelets to be low.

Protein and Antibody Tests

• Anti-Cyclic Citrullinated Peptide Antibody (Anti-CCP) is a blood test that is commonly ordered if rheumatoid arthritis is suspected.
  • A moderate to high level of anti-CCP essentially confirms the diagnosis in a person who has clinical signs of rheumatoid arthritis.
• Antinuclear antibodies (ANA): Antinuclear antibodies (ANA) are abnormal autoantibodies (immunoglobulins against nuclear components of the human cell). Moderate to high antinuclear antibody levels are suggestive of autoimmune disease.
• Positive antinuclear antibody tests are seen in:
  • More than 95% of systemic lupus erythematosus patients
  • 60% to 80% of scleroderma patients
  • 40% to 70% of patients with Sjögren’s syndrome
  • 30% to 50% of rheumatoid arthritis patients
• C-reactive protein (CRP): C-reactive protein is produced by the liver following tissue injury or inflammation.
  • Plasma levels of CRP increase quickly following periods of acute inflammation or infection, making this test a more accurate indicator of disease activity than the sedimentation rate, which changes more gradually.
• HLA tissue typing: Human leukocyte antigens (HLA) are proteins on the surface of cells. Specific HLA proteins are genetic markers for some of the rheumatic diseases.
  • Testing can determine if certain genetic makers.
• Erythrocyte sedimentation rate:- the erythrocyte sedimentation rate (ESR) is a nonspecific indicator of the presence of inflammation.
• Uric acid:  High levels of uric acid in the blood (known as hyperuricemia) can cause crystals to form which are deposited in the joints and tissues (gout).

2010 ACR/EULAR classification criteria test score

The 2010 ACR/EULAR classification criteria for RA are designed to identify patients with unexplained inflammatory arthritis in at least one peripheral joint and a short duration of symptoms who would benefit from early therapeutic intervention.

According to the ACR/EULAR criteria, patients who should be tested are those:

(1) who have at least one joint with definite clinical synovitis

(2) whose synovitis is not better explained by another disease (i.e. lupus, psoriatic arthritis, or gout).

The ACR/EULAR classification system is a score-based algorithm for RA that incorporates the following four factors:

• Joint involvement
• Serology test results
• Acute-phase reactant test results
• Patient self-reporting of the duration of signs and symptoms

Points tally

• The maximum number of points possible is 10.
• A classification of definitive RA requires a score of 6 or higher.
• Patients with a score lower than 6 should be reassessed over time. If patients already have erosive changes characteristic of RA, they meet the definition of RA and application of this diagnostic algorithm is unnecessary.

Joint involvement consists of swelling or tenderness upon examination. The presence of synovitis may be confirmed on imaging studies.

Points are allocated as follows:

• One large joint = 0 points
• Two to 10 large joints = 1 point
• One to three small joints (with or without involvement of large joints) = 2 points
• Four to 10 small joints (with or without involvement of large joints) = 3 points
• > 10 joints (at least one small joint, plus any combination of large and additional small joints or such joints as the temporomandibular, acromioclavicular, or sternoclavicular) = 5 points

At least one serology test result is needed for RA classification. Points are allocated as follows:

• Negative RF and negative ACPA test results = 0 points
• Low-positive RF or low-positive ACPA test result = 2 points
• High-positive RF or high-positive ACPA test result = 3 points

At least one abnormal result on an acute-phase reactant test is needed for classification. Local laboratory standards determine which results are normal and which are abnormal. Points are allocated as follows:

• Normal C-reactive protein (CRP) level and normal erythrocyte sedimentation rate (ESR) = 0 points
• Abnormal CRP level or abnormal ESR = 1 point

Points for the patient’s self-reporting of the duration of signs or symptoms of synovitis in clinically involved joints are allocated as follows:

• Less than 6 weeks = 0 points
• 6 weeks or more = 1 point

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