This is the reason why Macco et al. retrospectively analyzed data from 747 children (mean age of 11 years) suspected of AA to evaluate the predictive value of the Alvarado score and PAS compared with the AIR score, which includes fewer symptoms than the Alvarado score and PAS, but adds the CRP value and allows for different severity levels of rebound pain, leukocytosis, CRP, and polymorphonucleocytes. The gene discussed is CRP; the disease is Increased total leukocyte count.