Ayob F, et al. - Researchers analyzed studies published in MEDLINE, EMBASE, Cochrane Database, PsychINFO, PubMed and ClinicalTrials. Gov up to January 2018, reporting the efficacy of pre-operative biomarkers and imaging tests as predictors of post-operative delirium (POD) in patients undergoing non-cardiac surgery. They did not include animal studies, paediatric, cardiac and intracranial surgery in this analysis. Using the Quality In Prognosis Study tool, they evaluated the risk of bias. They analyzed 34 prospective cohort studies with 4424 patients. According to the findings, C-Reactive Protein (CRP) was identified as the most promising biomarker associated with POD. Serum tests [Interleukin-6, Insulin-like Growth Factor 1, CRP, cholinesterases, apolipoprotein-E genotype, leptin, hypovitaminosis, hypoalbuminaemia, gamma-amino butyric acid] were mentioned in 19 studies. Cerebral-spinal fluid tests (monoamine precursor, melatonin, acute phase proteins, S100B and neurofibrillary tangles) and imaging tests were described in 10 studies and 5 studies, respectively.