How to tell if i have juvenile idiopathic arthritis?

Peds rheumatologist: There is no blood test that can diagnose juvenile idiopathic arthritis. Child must have joint swelling on exam or active synovitis on an MRI of the joint that must be done with IV contrast (mri without contrast cannot detect active arthritis unless it is advanced), that is not due to infection or injury. Kids with suspected jia should be evaluated by a board certified pediatric rheumatologist.