Anticoagulated patients exhibit intact endogenous thrombin potential using ST Genesia unlike the Calibrated Automated Thrombogram

Background: The thrombin generation (TG) assay is a feasible but labor-intensive method for detecting global coagulation. It enables comprehensive assessment of anticoagulation, while drug-specific assays assess only exposure. Traditionally, the Calibrated Automated Thrombogram (CAT) has been used, however the ST Genesia (Diagnostica Stago) allows automated evaluation.

Objective: We aimed to observe coagulation using the ST Genesia and compare the data with those of CAT in anticoagulated patients.

Patients and methods: In total, 43 frozen-thawed samples were studied using DrugScreen to assess direct oral anticoagulants (DOACs), warfarin, and low-molecular-weight heparin. Twenty samples (nine rivaroxaban, five apixaban, three warfarin, and three heparin) were also compared using CAT (5 pM tissue factor).

Results: TG reduction in DrugScreen depended on the specific drug and modestly correlated with DOAC levels (lag time R² = 0.36; peak R² = 0.50). The best correlation was observed with peak thrombin and rivaroxaban-specified anti-activated factor X (anti-Xa) activity (R² = 0.60). When comparing ST Genesia with CAT, only the results for apixaban concorded (R² = 0.97). Unlike CAT, ST Genesia yielded a normal endogenous thrombin potential (ETP) in 77% (24/31) activated factor X inhibitor cases, and it failed to give readouts at international normalized ratio (INR) ≥4.5 and at anti-Xa ≥1.0 IU/mL.

Conclusion: The ST Genesia data did not correlate with CAT, but it was independently associated with INR, anti-Xa, and DOAC concentrations. The lag time and peak responses were similar; the major differences were that ST Genesia showed no ETP effect of DOACs and failed to give readout at high INR or anti-Xa activity.