Thursday, January 5, 2012

Blood Tests in Rheumatoid Arthritis

There are a myriad of lab tests associated with Rheumatoid Arthritis. What do these tests mean and why are they done?

One test your rheumatologist will probably order is the Rheumatoid Factor (RF). In seventy to eighty percent of people diagnosed with RA this test will be positive but twenty to thirty percent of RA sufferers will have a negative RF. Results may also change over the course of the disease.

Another test you may have done is the Anti-CCP Antibody test. This test may or may not be positive in RA but if it is positive, the likelihood of having RA is around ninety percent. The anti-CCP also indicates that the disease is likely to progress more rapidly.

The ANA or Anti-nuclear Antibody tests measure the immune-system chemicals that indicate autoimmune disease. Around thirty to forty percent of RA patients test positive for ANA. This test may also be positive in many other auto-immune diseases.

ESR or Erythrocyte Sedimentation Rate tests for inflammation by measuring how quickly red blood cells separate out of the blood and settle to the bottom of the tube.

Another test for inflammation is the CRP or C-Reactive Protein. This is a protein produced in the liver during periods of high inflammation or infection. These levels change more quickly than the ESR so this is a test used to measure the effectiveness of treatment.

A CBC or complete blood count is another test usually done. This gives the rheumatologist information regarding your hemoglobin, red blood cell count, platelet and white blood cell count. In RA, the platelets may be increased and since the white blood cells indicate immune system activity, they may also be increase. The hemoglobin may be decreased, indicating anemia.

A fairly new test on the market is the Vectra DA test. This test is a multi-biomarker blood test for RA disease activity. It measures twelve proteins associated with RA disease activity and integrates them into a single objective score. It has been validated for adults diagnosed with RA and is not a diagnostic tool but rather a disease activity indicator.

This list of tests is not all inclusive as your rheumatologist will determine which blood tests are appropriate for you. Other tests that may be done include, liver enzymes and kidney function tests, just to name a few.

Your rheumatologist will use all of the testing done in conjunction with your clinical picture to work with you and determine a plan of action for your treatment.

  1. Rheumatoid Arthritis Tests By the Healthline Editorial Team; Reviewed by Norstrom, Olag M. Sc., M.A. 07/29/2010
  2. Diagnostic Tests for Rheumatoid Arthritis by Nicole Van Hoey; March 11, 2010

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