Rheumatoid Factor Test

Rheumatoid factor test is used to measure the amount of rheumatoid factor in the blood. Rheumatoid factors are proteins produced by the body's immune system that can attack healthy tissue in the body. Antibodies are normal protein found in the blood, functioning within the immune system. Rheumatoid factor is an immunoglobulin i.e. antibody that can bind other antibodies. It may be present in 1-2% of the healthy population. In older people aged 65 and above, 20% have elevated level of rheumatoid factor.

Elevated levels of rheumatoid factor in the blood show up as autoimmune diseases, such as rheumatoid arthritis and Sjogren's syndrome. Many a time, rheumatoid factor may be detected in few healthy people and at times some people with autoimmune diseases have normal levels of rheumatoid factor. Patients with negative rheumatoid factor but suffering from the condition are classified as having seronegative rheumatoid arthritis. But largely, healthy people do not produce rheumatoid factor.

A sample of blood is drawn from the vein in the arm and sent to the laboratory for test. The RF test helps to diagnose rheumatoid arthritis and may also help the physician choose the line of treatment. A positive result, i.e. test result indicating the presence of rheumatoid factor in the blood may confirm rheumatoid arthritis in a person. About 80% of adults who have rheumatoid arthritis test high for rheumatoid factor.

This test helps differentiate between rheumatoid and inflammatory arthritis from other types of arthritis. High level of rheumatoid factor may also result from the presence of other autoimmune diseases in the body such as:

• Cancer
  
• Cirrhosis
  
• Scleroderma
  
• Sjogren's syndrome
  
• Chronic infections
  
• Mixed connective tissue disease
  
• Inflammatory lung disease like Sarcoidosis
• Systemic lupus erythematosus
  

When is the test ordered?

Rheumatoid factor test is ordered for persons suffering from the following symptoms:

• Stiffness in the joints
  
• Increased pain in the joints in the morning
  
• Bone loss
  
• Loss of cartilage
  
• Nodules under the skin
  
• Warmth and swelling in the joints.

Rheumatoid arthritis test principle

Rheumatoid factor can be identified in the laboratory by its ability to bind and form clumps with latex particles or red blood cells that have human immunoglobulin (IgG). If the patient being tested has rheumatoid factor, then it attaches to the IgG coating the latex particles causing lumps. This process is called agglutination. Agglutination is a positive reaction that indicates the presence of rheumatoid factor at a detectable level.

Rheumatoid Factor Results

The antibody titer is a test that measures the quantity of the blood that can be diluted before RF antibodies become indistinguishable. The following results will be considered as normal:
Less than 40 - 60 units/ml
Less than 1:80 (1 to 80) titer.

A low number (normal result) generally indicates that the person being tested does not have rheumatoid arthritis or Sjogren syndrome. However, a few people who have the condition may still have a normal or low rheumatoid factor (RF). Normal ranges may vary from laboratory to laboratory.

An abnormal result may mean the test is positive. Most patients with this result may have rheumatoid arthritis or Sjogren's syndrome. The higher the level, the more likely the condition is present. There are other tests that may be used to diagnose the condition.

• False positive results can occur when the fat content in the blood is high.
  
• Inaccurate results may show up when the blood specimen is handled improperly.
  
• A negative rheumatoid factor does not rule out the presence of rheumatoid arthritis.
  

Pyoderma Gangrenosum

Pyoderma gangrenosum is a rare condition with necrotic tissue causing deep and painful ulcers on the skin. Though it can affect any part of the skin, Pyoderma Gangrenosum often develops on the legs. The condition initially starts as small, red blisters and subsequently forms into painful deep and swollen open sores. The exact cause of Pyoderma gangrenosum is not known. However it is associated with dysfunction of immune system in the body. Those who are prone to this condition will have a tendency to develop ulcers at the site of wounds and cuts. People with following underlying conditions are also at the risk of developing Pyoderma Gangrenosum:

• Ulcerative colitis
  
• Crohn's disease
  
• Inflammatory bowel disease
  
• Rheumatoid arthritis
  
• Papa syndrome
  
• Myeloma
  
• Behcet's syndrome
  
• Acute myelogenous leukemia
  
• Chronic myelogenous leukemia

Symptoms of Pyoderma Gangrenosum

Large and open ulcer is the most obvious symptom of Pyoderma Gangrenosum. Ulcers are extremely painful and cause weakness in the body. The edge of the ulcer often looks purplish with fluid or pus oozing out of the ulcer.

Diagnosis

There is no specific test that confirms the condition. However few blood tests and a biopsy of the ulcer is usually ordered to decide on the course of treatment. Blood tests are conducted to check for the extent of infection and also for Liver, kidney and thyroid functions. Another blood test called rheumatoid factor test is also performed to assess rheumatoid arthritis, a condition associated with Pyoderma gangrenosum. Skin Biopsy is also carried out to confirm the diagnosis. The wound is swabbed and cultured to examine the bacteria under microscope.

Treatment of Pyoderma Gangrenosum

Pyoderma Gangrenosum requires immediate medical attention as it can progress quickly. Typically, non surgical treatment is followed in treating the condition which involves wound management, topical steroid ointments, oral steroid medications. Prednisolone is the most commonly used steroid medication along with antibiotics such as dapsone and minocycline to treat Pyoderma Gangrenosum. As this condition is believed to be the result of overactive immune system, Immunosuppressants such as ciclosporin, mycophenolate mofetil, and infliximab, are also used in severe cases.

The outlook for Pyoderma Gangrenosum is very positive as the ulcer eventually heals with medication. However, it tends to leave some scarring in the affected area.