BackgroundTo investigate the power of inflammation/immune indices in-hospital deep vein thrombosis (DVT) and any venous thromboembolism event (VTE: DVT + pulmonary emboli; PE) that may occur after trauma or surgery and to identify the strongest predictors. MethodsThis was a retrospective study conducted between January 2020 and December 2022. A total of 216 patients with suspicion of DVT or PE during their hospital stay for trauma or surgery were included in the study. Monocyte-lymphocyte ratio (MLR), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), systemic inflammatory index (SII), systemic inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI) were calculated. Participants were divided into the following 3 groups: Those without DVT or PE (Control group, n = 70), only DVT (DVT group, n = 71), and both DVT and PE (VTE group, n = 75). ResultsThe median D-dimer, NLR, PLR, MLR, SII, SIRI and AISI values of VTE group were significantly higher than both the control and DVT groups (p< 0.001 for all). The DVT group also had significantly higher values for these parameters compared to controls (p<0.001 for all). All of these indices had significantly high performance to detect DVT or PE (p<0.001 for all). Despite very high performance (some exceeding D-dimer measurement) detected for all examined parameters, AISI was the best predictor in both DVT and VTE (DVT + PE) prediction (AUC = 0.995 and 0.959, respectively) ConclusionThese indices, especially AISI, can play a role in the initial screening and risk stratification of patients at high risk of DVT or VTE after surgery or trauma.