CRP and appendicitis: Table 1 shows the age and sex of patients with complicated appendicitis, non-complicated appendicitis, and gangrenous and non-gangrenous appendicitis. To assess the difference in CRP concentration at different ages, we stratified the cohort into four different groups, as shown in Supplementary Figure 2 (Additional File 2). CRP concentration was significantly different between groups (p = 3.24 × 10−6) and seems to be increasing with age.