The diagnostic model constructed by this gene expression signature can reach an area under curve (AUC) of 0.83.530 Combinational use of anti-inflammatory and pro-inflammatory cytokines in serum, such as IL-4, IL-6, and TNF-α, has been proved as potential biomarkers of neuropathic pain or visceral hypersensitivity, with AUC at least 0.66.531–533 Metabolomics has led to the emergence of serum metabolites as pain biomarkers. This evidence concerns the gene IL4 and neuropathic pain.