Recently, we further demonstrated that a novel predictor utilizing a combination of the Z score of Hb and plasma hepcidin with a better discriminatory ability for differentiating from WBC, CRP, and Hb between children with Kawasaki disease—an acute multisystem vasculitis syndrome, which mostly affects genetically susceptible infants and children aged less than 5 years old [58]—and other febrile illnesses [30]. The gene discussed is CRP; the disease is Kawasaki disease.