Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX
Recommended laboratory tests for confirming juvenile idiopathic arthritis (JIA) and excluding other conditions include:
- Full blood count (FBC) to assess for anaemia or infection, which may mimic or complicate JIA NICE CKS.
- Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) as markers of systemic inflammation, supporting the diagnosis of JIA but not specific to it NICE CKS.
- Rheumatoid factor (RF) testing, which is positive in a minority of JIA cases and helps to classify subtypes but is not diagnostic alone NICE CKS.
- Antinuclear antibody (ANA) testing, useful for identifying patients at risk of uveitis and supporting diagnosis, though not definitive NICE CKS.
- Exclusion of infection or malignancy through relevant cultures or blood film if clinically indicated NICE CKS.
- Additional tests such as HLA-B27 may be considered in cases with enthesitis-related arthritis features NICE CKS.
These tests collectively help confirm JIA by demonstrating inflammation and excluding mimicking conditions such as infection, malignancy, or other rheumatological diseases. Recent pediatric rheumatology literature emphasizes the importance of a comprehensive panel including inflammatory markers, autoantibodies, and exclusion tests to improve diagnostic accuracy and guide management Pilania & Singh 2019.
Key References
- CKS - Rheumatoid arthritis
- NG100 - Rheumatoid arthritis in adults: management
- CKS - Childhood limp - acute
- CKS - Limp (childhood) - acute
- CKS - Acute childhood limp
- NG65 - Spondyloarthritis in over 16s: diagnosis and management
- NG143 - Fever in under 5s: assessment and initial management
- (Pilania and Singh, 2019): Rheumatology Panel in Pediatric Practice.