The Rheumatology Profile 5 (Mono Arthritis) Blood Test is designed to investigate the underlying causes of monoarthritis, which is inflammation or arthritis affecting a single joint. Monoarthritis can be due to a variety of causes, including infection, trauma, autoimmune diseases, or crystal-induced arthritis like gout or pseudogout. This test panel helps clinicians distinguish between these different causes and guides the appropriate treatment.

Components of the Rheumatology Profile 5 (Mono Arthritis) Blood Test:

1. Uric Acid

  • Purpose: Measures the level of uric acid in the blood.
  • Indication: Elevated uric acid levels suggest gout, a common cause of monoarthritis.
  • Abnormal Results: High uric acid levels indicate hyperuricemia, which is associated with gout. However, normal uric acid levels do not exclude gout as a diagnosis.

2. C-Reactive Protein (CRP)

  • Purpose: A marker of inflammation in the body.
  • Indication: Used to assess the presence and degree of inflammation, which can help differentiate between inflammatory and non-inflammatory causes of joint pain.
  • Abnormal Results: Elevated CRP indicates active inflammation, which can be caused by infections, gout, rheumatoid arthritis, or other inflammatory conditions affecting a single joint.

3. Erythrocyte Sedimentation Rate (ESR)

  • Purpose: Measures the rate at which red blood cells settle in a test tube, another nonspecific marker of inflammation.
  • Indication: Helps assess overall inflammation and is elevated in conditions such as infectious arthritis, rheumatoid arthritis, and gout.
  • Abnormal Results: An elevated ESR suggests inflammation but is not specific to any particular condition.

4. Rheumatoid Factor (RF)

  • Purpose: Detects rheumatoid factor, an antibody present in patients with rheumatoid arthritis (RA) and other autoimmune diseases.
  • Indication: While monoarthritis is not typical of rheumatoid arthritis, in rare cases, early RA may present with inflammation in a single joint.
  • Abnormal Results: Positive RF suggests the possibility of RA or other autoimmune conditions, though its presence is less likely in isolated monoarthritis.

5. Anti-Cyclic Citrullinated Peptide (Anti-CCP) Antibodies

  • Purpose: Detects antibodies that are highly specific to rheumatoid arthritis.
  • Indication: Anti-CCP antibodies are more specific than RF for diagnosing rheumatoid arthritis, particularly in its early stages.
  • Abnormal Results: Positive Anti-CCP antibodies suggest a higher likelihood of rheumatoid arthritis, even in patients who initially present with monoarthritis.

6. Antinuclear Antibody (ANA)

  • Purpose: Screens for antinuclear antibodies commonly found in autoimmune conditions like lupus.
  • Indication: ANA testing is used to evaluate whether autoimmune conditions like systemic lupus erythematosus could be causing joint inflammation.
  • Abnormal Results: A positive ANA can indicate autoimmune diseases such as lupus, though it is not typically associated with isolated monoarthritis.

7. Complete Blood Count (CBC)

  • Purpose: Measures the overall levels of red blood cells, white blood cells, haemoglobin, and platelets.
  • Indication: Useful for detecting anaemia, inflammation, and infection, which are common in autoimmune diseases like RA.
  • Abnormal Results: Low red blood cells (anaemia) or elevated white blood cells may suggest chronic inflammation or infection.

8. HLA B27

Conditions Often Assessed with Rheumatology Profile 5:

  • Gout: Caused by the accumulation of uric acid crystals in the joint, often affecting the big toe but can also affect other joints.
  • Pseudogout: Caused by calcium pyrophosphate crystals, often affecting larger joints like the knee.
  • Septic Arthritis: A bacterial infection in a joint, which can rapidly destroy the joint if not treated promptly.
  • Early Rheumatoid Arthritis: Though RA typically affects multiple joints, it may begin with inflammation in a single joint.
  • Trauma or Injury: Joint injury can also cause monoarthritis, which may be mistaken for inflammatory arthritis.

When Is the Rheumatology Profile 5 Test Ordered?

  • Acute Onset of Joint Pain: When a patient presents with sudden pain, swelling, and redness in a single joint, especially the knee, ankle, or big toe.
  • Suspected Gout or Pseudogout: To help confirm or rule out crystal-induced arthritis.
  • Suspected Septic Arthritis: If there is concern for an infection in the joint, especially if the patient has fever or a warm, swollen joint.
  • Screening for Autoimmune Diseases: In cases where early autoimmune disease is suspected as the cause of joint pain.

Interpretation of Results:

  • Elevated Uric Acid: Suggestive of gout but must be interpreted in conjunction with clinical findings and synovial fluid analysis.
  • Elevated CRP/ESR: Indicates active inflammation, which could be due to infection, gout, or autoimmune conditions.
  • Positive RF or Anti-CCP: May suggest early rheumatoid arthritis, though this is less likely in isolated monoarthritis.
  • Synovial Fluid Findings: Presence of crystals (uric acid or calcium pyrophosphate) confirms gout or pseudogout. Presence of bacteria suggests septic arthritis.

Conclusion:

The Rheumatology Profile 5 (Mono Arthritis) Blood Test is essential for diagnosing the cause of inflammation in a single joint. This panel aids in distinguishing between infectious causes (septic arthritis), crystal-induced conditions (gout or pseudogout), and autoimmune diseases. It is often used alongside joint aspiration and synovial fluid analysis to provide a clear diagnosis and guide treatment strategies.

Results – 3 days from Laboratory receiving sample

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