Objectives: To investigate the diagnostic value of fibrinogen (FIB) in patients with rib fractures complicated by lower extremity deep venous thrombosis (DVT). Methods: Analyzing data from 493 patients at Shijiazhuang Third Hospital, FIB levels at 24, 48, and 72 h post-injury were compared between DVT and non-DVT groups. Results: DVT group had elevated FIB levels at all times ( p < .001). FIB at 24 h showed highest AUC, particularly in patients with BMI <28. Conclusion: In conclusion, measuring FIB at 24 h post-injury enhances DVT detection in rib fracture patients, with potential BMI-related variations.