The search terms used included combinations of Medical Subject Headings (MeSH) and keywords such as “C-reactive protein,” “neutrophil-to-lymphocyte ratio,” “postoperative infection,” “gastrointestinal surgery,” and “predictive biomarkers.” All retrieved records were imported into EndNote X9 (Clarivate Analytics, Philadelphia, PA, USA) to remove duplicates prior to screening. This evidence concerns the gene CRP and infection.