Objective: To develop a rapid quantification method for neutrophil extracellular traps (NETs) by quantifying neutrophils forming NETs (NETotic cells) on routine peripheral blood smears, and to evaluate the performance of an early warning model combining NETs with traditional coagulation indicators for risk of sepsis-induced coagulopathy (SIC) in septic patients. Methods: This prospective observational study was conducted in Wuxi People's Hospital Affiliated with Nanjing Medical University between May 2023 and May 2025. A total of 147 patients with sepsis (diagnosed based on Sepsis-3.0 criteria) who had not developed SIC [the international society on thrombosis and haemostasis (ISTH SIC score <4)] were enrolled. Blood samples were collected within 2 hours of admission. Neutrophil smudge cells (NETs%) were counted using an automated cell morphology analyzer. Serum levels of myeloperoxidase-DNA (MPO-DNA) complexes, circulating free DNA (cf-DNA) and sequential organ failure assessment (SOFA) scores were also determined. Based on progression to SIC (ISTH score ≥4) within 72 hours of admission, patients were categorized into a sepsis without SIC group (n=85) and a sepsis with SIC group (n=62). Risk factors were analyzed using binary logistic regression, receiver operating characteristic (ROC) curves were plotted, and the predictive value of NETs%, SOFA, and AT-Ⅲ for coagulation dysfunction was assessed. Results: The NETs% level was significantly higher in the sepsis with SIC group [8.50% (7.00, 11.50)] compared to both the healthy control group [1.00% (0.00, 2.00)] and sepsis without SIC group [4.40%(3.50, 6.50)] (P<0.01). NETs% was identified as an independent risk factor for SIC in sepsis patients. ROC analysis showed that the area under the curve (AUC) for predicting SIC was 0.90 for NETs%, 0.85 for MPO-DNA, and 0.79 for cf-DNA. The combined model of NETs% and SOFA score demonstrated the best performance, with an optimal cut-off value of 0.33, an AUC of 0.92, a sensitivity of 77%, and a specificity of 93%. Conclusion: NETs% shows promise as a novel biomarker for SIC. Peripheral blood smear morphology provides a simple, rapid, and cost-effective method for quantifying NETs%. NETs% enhances the early clinical identification of patients at high risk for SIC, and its combination with the SOFA score facilitates SIC prediction, offering a critical time window for initiating timely preventive interventions.