Labs are tools to help diagnose RA, distinguish it from other forms of arthritis, determine its severity and monitor key body functions for the liver and kidneys during treatment.
Rheumatoid Factor (RF)
Rheumatoid Factor is an autoantibody that is produced by the body’s immune system. Autoantibodies, made by the B cells, attack a person’s own antibodies. The presence of Rheumatoid Factor is an indicator of inflammatory and autoimmune activity.
Elevated in about 80% of those diagnosed with RA. Some link the severity of RA with the degree of elevation. The RF may also be elevated in those with Lupus, endocarditis, cancer and a variety of other disorders. My RA is considered sero-negative as my RF factor was not elevated.
Cyclic Citrullinated Peptide Antibody(CCP)
This antibody is more specific to RA than the RF. It has a low sensitivity so may be normal in the presence of RA. There is a strong case for RA when both the CCP and the RF are elevated.
My RA is considered to be a classic case although both my RF and my CCP were normal.
Erythrocyte sedimentation rate(ESR, SED rate)
There is inflammation present in the body when the ESR is elevated. It is used to help diagnose and to monitor RA. The ERS is not elevated in the presence of osteoarthritis. My ESR was off the charts.
There is inflammation in the body when the CRP is elevated. It is used to help diagnose and to monitor RA. The CRP is not elevated in the presence of osteoarthritis. My CRP was off the charts.
Complete Blood Count(CBC)
This is a group of tests. It includes red and white blood cells, platelets, hemoglobin and hematocrit. This is a complex test as is the metabolic panel. The red blood cell count may be lowered reflecting anemia. The white blood cell count may be elevated with infection or severe inflammation. Neutrophils, a subset of white blood cells, are frequently elevated in RA reflecting inflammation. Lymphocytes are decreased as an inverse relationship to the neutrophils.
Comprehensive Metabolic Panel(CMP)
This is a group of tests that include substances that monitor liver and kidney function. It is important in assessing how well RA drugs are being tolerated by the body.
These are a few key lab tests used in the management of RA. There are more and I will expand my information with time.