Fig. 2

Comprehensive analysis of untargeted metabolomics of serum from patients with sepsis and normal controls. A The number of metabolites detected in positive and negative ion modes. B The proportion of the identified metabolites in each chemical classification. C Principal component analysis (PCA) of the identified metabolites showing that patients with sepsis differed from normal controls (NC) in both positive ion mode (left) and negative ion mode (right). D The volcano plot of differentially expressed metabolites (DEMs) between patients with sepsis and NCs in positive ion mode (left) and negative ion mode (right). The metabolites whose expression increased in sepsis are shown in red and those whose expression decreased are shown in blue. E–F Pathway analysis of upregulated and downregulated metabolites