From the Guidelines
Laboratory tests are not required to establish an osteoarthritis diagnosis, but may be ordered to rule out other conditions that can mimic or coexist with OA. The diagnosis of osteoarthritis (OA) primarily relies on the patient's symptoms, physical examination findings, and radiographic changes such as joint space narrowing, osteophyte formation, subchondral sclerosis, and cyst formation 1. There are no specific blood tests or laboratory markers that can definitively diagnose osteoarthritis. However, laboratory tests may be ordered to rule out other conditions that can mimic or coexist with OA, such as rheumatoid arthritis or gout. These tests might include:
- Complete blood count (CBC)
- Erythrocyte sedimentation rate (ESR)
- C-reactive protein (CRP)
- Rheumatoid factor (RF)
- Anti-cyclic citrullinated peptide (anti-CCP) antibodies
- Uric acid levels Normal inflammatory markers like ESR and CRP can help differentiate OA from inflammatory arthritis, as these values are typically not elevated in osteoarthritis 1. Joint fluid analysis may occasionally be performed if there is significant joint effusion or if infection or crystal arthropathy is suspected. Imaging studies, such as plain radiographs, are the gold standard for morphological assessment of OA, and can help confirm the diagnosis 1. In summary, laboratory tests serve mainly to exclude other diagnoses rather than to confirm OA, and the diagnosis of OA should be based on a combination of clinical evaluation, patient history, and imaging studies 1.
From the Research
Laboratory Tests for Osteoarthritis Diagnosis
To establish an osteoarthritis (OA) diagnosis, several laboratory tests can be ordered, including:
- Erythrocyte sedimentation rate (ESR) 2
- High-sensitivity C-reactive protein (CRP) 2, 3
- Monomeric C-reactive protein (mCRP) 3
- Rheumatoid factor (RF) 4, 5
- Anti-cyclic citrullinated peptide (CCP) antibodies 4
- Matrix metalloproteinase-3 (MMP-3) 4
Rationale for Laboratory Tests
These laboratory tests are used to:
- Evaluate inflammation and disease activity in OA patients 2, 3
- Distinguish OA from other rheumatic diseases, such as rheumatoid arthritis (RA) 4, 5
- Monitor disease progression and response to treatment 3
Specific Laboratory Tests for OA
- ESR and CRP are commonly used to assess inflammation in OA patients 2
- mCRP has been shown to be associated with OA and may be a potential biomarker for disease activity 3
- RF and anti-CCP antibodies are typically used to diagnose RA, but can also be elevated in OA patients 4, 5
- MMP-3 has been studied as a potential biomarker for OA, but its diagnostic utility is still being investigated 4