CRP and abscess: DeLong’s test showed that the risk-score model significantly outperformed the individual predictors: CRP (AUC=0.73, 95 % CI 0.66–0.80, p = 0.001), abscess diameter (AUC=0.72, 95 % CI 0.64–0.80, p < 0.001), and RPE (AUC=0.71, 95 % CI 0.65–0.77, p < 0.001) (p-values for AUC comparisons) (Fig. 2).