Related Experiment Video
Updated: Apr 16, 2026

In Vitro Thrombosis Test for Ventricular Assist Devices
Published on: March 21, 2025
Assessing the anticoagulant effect of dabigatran in children: an in vitro study
Kevin Dietrich1, Linda Stang2, Joanne van Ryn3
1Division of Hematology/Oncology, Department of Pediatrics, University of Alberta, Edmonton, Alberta Canada T6G 2S2.
Insights
The dilute thrombin time (dTT) assay is optimal for measuring dabigatran in children. Dabigatran
Area of Science:
- Pharmacology and Toxicology
- Hematology and Coagulation
Background:
- Hemostatic system undergoes age-related changes influencing anticoagulant responses in children.
- Dabigatran, a direct thrombin inhibitor, requires validated monitoring in pediatric populations.
Purpose of the Study:
- To identify optimal coagulation assays for monitoring dabigatran therapy in pediatric patients.
- To evaluate the anticoagulant effect of dabigatran across diverse pediatric age groups using in vitro methods.
Main Methods:
- Pooled plasma from children (0-<17 years) and adults were spiked with varying dabigatran concentrations.
- Effect of dabigatran was assessed using five coagulation assays and a fibrin clot formation/lysis assay.
Main Results:
- No significant differences in dabigatran response were observed across pediatric age groups in any assay.
- Dilute thrombin time (dTT), thrombin time (TT), and ecarin clotting time showed linear correlation with dabigatran.
- Fibrin clot formation and lysis assays demonstrated consistent and adult-comparable responses to dabigatran in children.
Conclusions:
- Dilute thrombin time (dTT) is the most suitable assay for measuring dabigatran concentrations in children.
- Fibrin clot generation and lysis assays provide reliable and age-independent assessment of dabigatran's effect in pediatric patients.
Objectives:
Age-related changes in the hemostatic system result in variation in response to anticoagulants and coagulation assays over childhood. This study used in vitro methods to determine i) optimum coagulation assays for dabigatran in children and ii) anticoagulant effect of dabigatran across pediatric age groups.
Materials And Methods:
Pooled plasma samples from healthy children aged 0 to <1, 1 to <5, 5 to <10, 10 to <17 years and adults were spiked with increasing concentrations of dabigatran and the effect was assessed in five coagulation assays. The samples were also assessed for overall hemostasis potential using a fibrin clot formation and lysis assay.
Results:
In all five coagulation assays, there were no differences in responses to dabigatran over all pediatric age groups. The international normalized ratio was the least sensitive measure. Activated partial thromboplastin time showed moderate sensitivity and a nonlinear response curve. Thrombin time (TT), dilute TT (dTT) and ecarin clotting time were linearly correlated with dabigatran concentrations; however, the ecarin time and TT were overly sensitive. In the overall hemostasis potential assay, increasing dabigatran concentrations delayed the initiation of clot formation and reduced the time to 50% clot lysis. The responses to initiation of clot formation and clot lysis were consistent across all pediatric groups and comparable to responses in adults.
Conclusion:
The dTT is the most suitable assay for measuring dabigatran concentrations in children. Fibrin clot generation and lysis assay responses to dabigatran in children over all ages were consistent and comparable to those of adults.
Related Concept Videos
Anticoagulant Drugs: Vitamin K Antagonists and Direct Oral Anticoagulants
Warfarin, a prominent vitamin K antagonist family member, exerts its effect by inhibiting the enzyme VKORC1 (vitamin K epoxide reductase complex 1). By hindering this enzyme, warfarin...
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Effects of EDTA on End-Point Detection Methods
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a...

