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Updated: Aug 10, 2026
Leveraging Turbidity and Thromboelastography for Complementary Clot Characterization
Published on: June 4, 2020
[Reproducibility and interchangeability of the Thromboelastograph, Sonoclot and Hemochron activated coagulation time
F Forestier1, S Bélisle, C Contant
1Département D'anesthésiologie, Institut de Cardiologie de Montréal, Montréal, Québec, Canada.
Insights
The Thromboelastograph (TEG) offers the most reproducible on-site hemostasis monitoring in cardiac surgery. Other tests like Sonoclot (SCT) and Hemochron are less reproducible, and results are not interchangeable in heparinized patients during cardiopulmonary bypass.
Area of Science:
- Cardiovascular Surgery
- Hemostasis Monitoring
- Point-of-Care Testing
Background:
- On-site hemostasis monitoring is crucial in cardiac surgery.
- Reproducibility of Thromboelastograph (TEG), Sonoclot (SCT), and Activated Coagulation Time (ACT) devices is not well-established in clinical settings.
Purpose of the Study:
- To determine the reproducibility of TEG, SCT, and Hemochron ACT measurements (ACT-C, ACT-K) during on-site hemostasis monitoring.
- To evaluate the interchangeability of ACT-K and SCT with ACT-C under various clinical conditions.
Main Methods:
- Blood samples from 20 volunteers and 21 cardiac surgery patients were analyzed.
- TEG, SCT, and Hemochron analyzers were used.
- Variation rate (V%) was calculated for each parameter; interchangeability was assessed.
Main Results:
- TEG demonstrated the highest reproducibility (3.1-9.5% V%), followed by Hemochron (5.6-12.4% V%) and SCT (5.8-33.6% V%).
- ACT-C and ACT-K were interchangeable in non-heparinized patients.
- No other test could substitute for ACT-C in heparinized patients during cardiopulmonary bypass (CPB).
Conclusions:
- TEG provides the most reproducible on-site hemostasis measurements, followed by Hemochron and SCT.
- Instrument-specific values are essential for monitoring anticoagulation in heparinized patients during CPB due to non-interchangeable results.
Purpose:
Despite their common use in cardiac surgery, few studies have evaluated the reproducibility of the Thromboelastograph (TEG), of the Sonoclot (SCT), and of the activated coagulation time with celite (ACT-C) or kaolin (ACT-K) measured with the Hemochron, in clinical conditions of on-site monitoring of hemostasis. This study determined the reproducibility of those measurements, and evaluated the ability of various devices to substitute for the ACT-C.
Methods:
Blood samples collected from 20 volunteers and 21 patients undergoing myocardial revascularization were analyzed in the two channels of the TEG, in two SCT and four Hemochron analyzers. The overall of TEG and SCT coagulation profiles were analyzed by a computerized TEG and an experienced observer respectively. The variation rate (V%) was calculated for each variable. The ability of ACT-K and SCT to substitute for ACT-C under different clinical conditions was evaluated.
Results:
ACT-C and ACT-K V% ranged between 5.6% and 10.8% and between 6.7% and 12.4% respectively. TEG and SCT V% ranged between 3.1% and 9.5% and between 5.8% and 33.6% respectively, according to different conditions and parameters. In volunteers and non-heparinized patients, the ACT-C and ACT-K were interchangeable. No other test can substitute for the ACT-C when patients are heparinized during cardiopulmonary bypass (CPB).
Conclusions:
In the clinical conditions of use, on-site hemostasis monitoring devices providing the most reproducible measurements are, in decreasing order, the TEG, the Hemochron and the SCT. In heparinized patients and during CPB, results from different tests are not interchangeable, stressing the importance of establishing appropriate instrument-specific values for monitoring anticoagulation during cardiac surgery.
