From the Guidelines
Rheumatoid arthritis (RA) diagnosis should be approached through a combination of blood tests, imaging, and clinical evaluation, prioritizing tests such as rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies, as they are predictive of RA diagnosis and prognosis 1. The most common blood tests for RA diagnosis include RF, anti-CCP, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) 1.
- RF is present in about 80% of RA patients
- anti-CCP is more specific for RA and can appear years before symptoms develop
- ESR and CRP measure inflammation levels in the body Complete blood count may show anemia, which is common in chronic inflammation. Imaging tests such as X-rays can detect joint damage, while ultrasound and MRI can identify early joint inflammation before damage occurs 1. It's essential to note that no single test can definitively diagnose RA; rather, these tests combined with physical examination and symptom history help rheumatologists make an accurate diagnosis. Early testing is crucial as prompt treatment can prevent joint damage and improve long-term outcomes. If you suspect RA, consult a healthcare provider for appropriate testing and evaluation, which may include a complete rheumatologic history and examination, plain X-ray or imaging, and autoimmune blood panel including ANA, RF, anti-CCP, and inflammatory markers (ESR and CRP) 1.
From the Research
Rheumatoid Arthritis Diagnosis
- Rheumatoid arthritis is the most commonly diagnosed systemic inflammatory arthritis, with a lifetime prevalence of up to 1% worldwide 2.
- The diagnosis of rheumatoid arthritis is based on criteria that include having at least one joint with definite swelling that is not explained by another disease 3, 2.
- The likelihood of a rheumatoid arthritis diagnosis increases with the number of small joints involved 3.
Laboratory Tests for Rheumatoid Arthritis
- Laboratory tests, such as rheumatoid factor, anti-citrullinated protein antibody, C-reactive protein, and erythrocyte sedimentation rate, can be helpful in diagnosing rheumatoid arthritis 3, 2, 4, 5, 6.
- However, these tests have limitations, and a negative result does not rule out the diagnosis of rheumatoid arthritis 4.
- The presence of a rheumatoid factor or anti-citrullinated protein antibody, or elevated C-reactive protein level or erythrocyte sedimentation rate, suggests a diagnosis of rheumatoid arthritis 3, 2.
Biomarkers for Rheumatoid Arthritis
- Biomarkers, such as C-reactive protein, rheumatoid factor, anti-cyclic citrullinated protein, 14-3-3η protein, and the multi-biomarker disease activity score, can be used in the diagnosis and monitoring of rheumatoid arthritis 6.
- These biomarkers can help predict disease activity, joint damage, and response to treatment 6.
- The multi-biomarker disease activity score can differentiate between small differences in disease activity and predict radiographic progression of rheumatoid arthritis 6.