Your doctor will ask questions about your child's symptoms and past health and will do a physical exam. This includes understanding the pattern and nature of joint symptoms.

Lab tests may be used to support the diagnosis and make sure symptoms aren't caused by another health problem.

JIA is often diagnosed only after other possible causes of symptoms have been ruled out and the pain and stiffness have lasted for at least 6 weeks.

Routine exams and tests include:

• Complete blood count (CBC).
• Erythrocyte sedimentation rate (ESR, or sed rate).
• Urinalysis.
• Rapid strep test or throat culture (to test for strep throat).

Other tests that are done if needed include:

• Rheumatoid factor (RF). This test can clarify whether a child with polyarticular JIA is RF-positive or RF-negative.
• Antinuclear antibody (ANA). This test can clarify a child's type of JIA and risk for eye disease.
• X-ray of joints.
• An MRI scan. It may reveal early joint damage.
• HLA-B27 genetic test.

Your doctor will probably schedule routine checkups to see how your child is doing and how well treatment is working. This will include talking about inflammatory eye disease and exams for this disease, such as a slit lamp eye exam.