CALCA and infection: Univariate meta-regression analysis revealed that the sensitivity of heterogeneity among included studies might be attributable to several relevant factors, such as the risk of bias (low risk or high risk), publication years (until 2015 or after 2015), prevalence of infection (< 50% or ≥ 50%), sample size (< 100 or ≥ 100), study setting (inside ICU or outside ICU), clinical diagnostic criteria (sepsis-1, 2 or sepsis-3), and the cutoff value for each biomarker (< 1.0 or ≥ 1.0 for PCT, < 500 or ≥ 500 for P-SEP) (Fig. 5).