Understanding Lab Tests for Juvenile Rheumatoid Arthritis
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Juvenile Rheumatoid Arthritis (JRA), also known as Juvenile Idiopathic Arthritis (JIA), is a chronic autoimmune condition affecting children under 16 years of age. While there is no single blood test that can definitively diagnose JRA, laboratory testing plays a crucial role in assessing genetic risk factors, ruling out other conditions, and monitoring disease activity.
Top Recommended Test
HLA-B27 Antigen
This test detects the HLA-B27 antigen, a genetic marker found on white blood cells. Children who test positive for HLA-B27 have a higher likelihood of developing juvenile rheumatoid arthritis, particularly the enthesitis-related form of juvenile idiopathic arthritis. This information helps healthcare providers assess risk and monitor for early signs of the condition.
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The Role of Blood Testing in JRA
Diagnosis of JRA is primarily based on clinical symptoms and physical examination findings. However, blood tests are fundamental for identifying genetic markers that may indicate increased risk for certain subtypes of the condition, particularly the enthesitis-related form of juvenile idiopathic arthritis.
Other Relevant Tests
HLA B Low Resolution
This broader HLA-B typing test provides genetic information about various HLA-B markers, including HLA-B27. The presence of specific HLA-B markers, particularly HLA-B27, is associated with an increased risk of developing juvenile rheumatoid arthritis. This test offers a more comprehensive view of genetic risk factors that may influence disease susceptibility.
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Understanding Your Results
It's important to understand that testing positive for HLA-B27 or other genetic markers does not guarantee that a child will develop JRA. These tests indicate genetic predisposition rather than active disease. Many people with these markers never develop arthritis, while some with JRA may not carry these genetic factors.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.
