CRP and Chorea: Elevated acute phase reactants support the diagnosis: erythrocyte sedimentation rate (ESR) ≥ 60 mm/h and C-reactive protein (CRP) ≥ 3 mg/dL (≥30 mg/L); lower ranges of CRP and ESR can be seen in high-risk groups and in the setting of isolated chorea (late feature) or following anti-inflammatory treatment when acute phase reactant levels may have returned to normal.