Inflammatory Biomarker Series: Rheumatoid Factor
What are inflammatory biomarkers?
The purpose of measuring an inflammatory biomarker is to detect inflammation, which can assist clinicians in the identification of a particular disease or provide a marker of treatment response. Inflammation, either chronic or acute, is the body’s immune response to protect against harmful stimuli such as damaged cells, irritants or pathogens.1 When inflammation occurs in the body, extra protein is released from the site of inflammation and circulates in the bloodstream.2 It is these proteins, or antibodies, which clinicians are testing for in the blood as they can indicate if inflammation is present.
Like many inflammatory biomarkers, such as rheumatoid factor (RF), C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR), further tests will be required as testing for these tests alone does not provide a clearly defined diagnosis. However inflammatory biomarker tests can provide clinicians with a good indication of what may be wrong with a patient, which is why they are commonly tested for in a clinical setting.
What is Rheumatoid Factor?
Rheumatoid factor (RF) is an autoantibody which can target and damage healthy body tissue and in turn cause inflammatory symptoms.3 It is uncommon for this antibody to be present in healthy individuals, which is why it is a beneficial test to aid the diagnostic process. In particular, rheumatoid factor can be used as an inflammatory biomarker to assist in the diagnosis of rheumatoid arthritis (RA). However the rheumatoid factor antibody can also be present in healthy individuals or patients with systemic lupus erythematosus, liver cirrhosis, Sjögren’s Syndrome, Hepatitis and other conditions.4 If a test detects rheumatoid factor levels above 14 IU/ml, this is considered abnormally high.3
What is Rheumatoid Arthritis?
Rheumatoid arthritis is an autoimmune disease which attacks the lining tissue of joints, resulting in chronic inflammation. This disease commonly affects the hands, feet and wrists, with symptoms causing pain, fatigue and loss of bodily function and over time may even lead to multiple organ damage.5 Although diagnosis of rheumatoid arthritis requires a physical examination, testing for rheumatoid factor can be beneficial to assist in the diagnosis of this disease. Other blood tests that can be used to detect biomarkers associated with rheumatoid arthritis include C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), IgA, IgG, IgM and anti-cyclic citrullinated peptide (anti-CCP).
For health professionals
Randox Laboratories offer a leading portfolio of diagnostic reagents which includes a test for rheumatoid factor, with applications available for a range of biochemistry analysers. With a measuring range of 6.72 – 104 lU/ml, this assay can comfortably detect levels outside the normal range. Randox offer a complete diagnostic package for the screening of rheumatoid factor with a range of kit sizes, controls and calibrators available. Other inflammatory biomarker tests available from Randox include CRP, High Sensitivity CRP, Full Range CRP, IgA, IgG and IgM.
1. Nordqvist, C. Inflammation: Causes, Symptoms and Treatment. Medical News Today, https://goo.gl/rT4WS9 (accessed 16 January 2017)
2. Harding, M., Blood Tests to Detect Inflammation, Patient, 2015, https://goo.gl/F4OGrz, (accessed 16 January 2017)
3. Shiel, W. C., Rheumatoid Factor (RF), MedicineNet, 2016, https://goo.gl/XPA69u 2016 (accessed 16 January 2017)
4. Rheumatoid Arthritis Organisation, Rheumatoid Factor Test, Rheumatoid Arthritis Organisation, 2016, https://goo.gl/JujE5a
5. Gibofsky, A. Overview of Epidemiology, Pathophysiology and Diagnosis of Rheumatoid Arthritis. The American Journal of Managed Care. Vol.18, No.13. p.295-302, 2012