Laboratory tests performed in patients with suspicion of JIA include the complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), antinuclear antibody test (ANA), rheumatoid factor (RF), human leukocyte antigen B27 (HLA-B27) and human leukocyte antigen Cw6 (HLA-Cw6) [11]. This evidence concerns the gene CRP and juvenile idiopathic arthritis.