Some of the main blood tests used include: erythrocyte sedimentation rate (ESR) – which can help assess levels of inflammation in the body. C-reactive protein (CRP) – another test that can help measure inflammation levels.
Blood tests
People with rheumatoid arthritis often have an elevated erythrocyte sedimentation rate (ESR, also known as sed rate) or C-reactive protein (CRP) level, which may indicate the presence of an inflammatory process in the body.
Anti-cyclic citrullinated peptide antibody (anti-CCP).
This blood test checks for anti-CCP antibodies, which appear in many people with rheumatoid arthritis. In addition, anti-CCP can appear before RA symptoms develop, which can help doctors diagnose the disease early.
A positive (abnormal) result means that a higher level of rheumatoid factor was found in your blood. This doesn't always mean that rheumatoid factors are causing your symptoms. But the higher your RF test results, the more likely it is that you have a condition linked to rheumatoid factors.
Anti-CCP antibody test (ACCP or CCP). This test is for a type of autoantibody called cyclic citrullinated peptide (CCP) antibodies, which can be found in the blood of 60% to 80% of people with rheumatoid arthritis. The test is often conducted along with an RF test.
Another potential marker for increased risk of RA may be C-reactive protein (CRP), since CRP is a sensitive marker of systemic inflammation and is elevated in patients with RA.
No single blood test can reliably diagnose RA. Some healthy people test positive for anti-CCPs, while others who have RA have negative test results. Blood tests are just one of several factors, including a medical history, physical exam and X-rays, that help doctors diagnose the disease.
Blood testing
The only appropriate rheumatology “screening” laboratory tests are the acute phase reactants, either the erythrocyte sedimentation rate (ESR) or the C-reactive protein (CRP). These tests are almost always elevated in any inflammatory rheumatic disease.
The symptoms of rheumatoid arthritis often develop gradually over several weeks, but some cases can progress quickly over a number of days. The symptoms vary from person to person. They can come and go, and may change over time.
No blood test can definitively prove or rule out a diagnosis of rheumatoid arthritis, but several tests can show indications of the condition. Some of the main blood tests used include: erythrocyte sedimentation rate (ESR) – which can help assess levels of inflammation in the body.
Rheumatoid Factor (RF)
It is usually used to diagnose rheumatoid arthritis, but it can also detect juvenile arthritis, lupus, certain infections like tuberculosis, some types of cancer such as leukemia, and other autoimmune disorders.
What are inflammatory markers? Inflammatory markers are blood tests used by doctors to detect inflammation in the body, caused by many diseases. This can include infections, auto-immune conditions and cancers.
Lupus and Scleroderma
The autoimmune diseases systemic lupus erythematosus and scleroderma are two separate conditions but often present with joint involvement that mimics rheumatoid arthritis.
Rheumatoid arthritis causes visible damage to joints. Fibromyalgia does not. Rheumatoid arthritis also gets progressively worse, causing swelling and sometimes deformities. The pain from fibromyalgia is more widespread, while rheumatoid arthritis is concentrated initially to hands, wrists, knees and balls of the feet.
Inflammatory markers such as the ESR or C-reactive protein (CRP) are normal in about 60% of patients with early RA.
RA causes inflammation. In response, the body releases CRP into the bloodstream. Doctors measure CRP levels as part of the diagnosis and management of RA. While many factors influence a person's CRP levels, and there is no definitive normal range, CRP levels above 10 mg/l suggest substantial inflammation.
C-reactive protein (CRP) is routinely assessed as a marker of systemic inflammation in rheumatoid arthritis (RA). However, it is also an immune regulator that plays an important role in inflammatory pathways associated with RA and promotes atherogenic effects.
Generally, a CRP level of less than 10 mg/L is considered normal. CRP levels between 10 and 100 mg/L indicate mild to moderate inflammation, while levels above 100 mg/L indicate severe inflammation.
People with rheumatoid arthritis typically have several permanently inflamed joints. The inflammation inside the body can lead to general physical weakness, drowsiness and exhaustion. This feeling of extreme tiredness is also called "fatigue." Some people find this to be the worst symptom of the disease.
Rheumatoid arthritis (RA)
When a person has RA, the immune system attacks healthy cells in the body for unknown reasons, causing an inflammatory response. RA commonly affects the hips, knees, ankles, or feet. Therefore, it can cause leg pain.
The main difference between osteoarthritis and rheumatoid arthritis is the cause behind the joint symptoms. Osteoarthritis is caused by mechanical wear and tear on joints. Rheumatoid arthritis is an autoimmune disease in which the body's own immune system attacks the body's joints.