Thrombin Generation Assays in Clinical Hemostasis: From Mechanistic Insights to Clinical Applications

Background: Thrombin plays a central role in hemostasis, serving as both the primary enzyme driving fibrin formation and central regulator of anticoagulant pathways. Routine coagulation assays such as prothrombin time and activated partial thromboplastin time capture only a limited fraction of thrombin’s role, overlooking inhibitory pathways and downstream regulation. Thrombin generation assays (TGA) provide a global view of coagulation, measuring both formation and inhibition of thrombin over time. Methods: We conducted a narrative literature review using PubMed and Embase up to January 2025, focusing on publications evaluating TGA methodology, clinical applications, and translational potential. Additional references were identified through citation review. Results: TGA generate thrombin activity curves, from which parameters such as lag time, peak thrombin, time-to-peak, velocity index, and endogenous thrombin potential are derived. These parameters reflect hyper- or hypocoagulability and have been linked to clinical outcomes. Applications include monitoring anticoagulant therapy and reversal strategies, predicting venous thromboembolism recurrence, assessing thrombotic risk in cardiovascular disease and antiphospholipid syndrome, and stratifying bleeding risk in bleeding disorders. TGA can also evaluate the efficacy of bypassing agents and novel hemostatic drugs in ex vivo settings. Barriers include technical complexity, pre-analytical variability, and lack of standardization across laboratories. Conclusion: TGA provide a global assessment of coagulation, demonstrating added value in both hyper- and hypocoagulable states. While most data remain research-based, growing evidence supports their utility in thrombotic risk prediction and bleeding risk assessment. Wider adoption in clinical practice will depend on assay standardization, validation in multicentre studies, and integration into clinical decision-making pathways.