The Ecarin Clotting Time, a Universal Method to Quantify Direct Thrombin Inhibitors
Research Group Pharmacological Haemostaseology, Medical Faculty, Friedrich Schiller University Jena, Jena, Germany. Pathophysiology of Haemostasis and Thrombosis
(Impact Factor: 2.24).
01/2003; 33(4):173-83. DOI: 10.1159/000081505
The ecarin clotting time (ECT) is a meizothrombin generation test that allows for precise quantification of direct thrombin inhibitors. The ECT has demonstrated its usefulness for more than 10 years in biochemical-pharmacological investigations as well as in clinical research and in the clinical routine. It has proved valuable especially as a drug-monitoring method in r-hirudin therapy. This test has been adjusted to clinical requirements by numerous modifications. Following the description of the biochemical background and the measuring principle of the ECT, this article gives a short survey of several modifications of the ECT for both preclinical and clinical use, e.g., for biochemical investigations, as a point-of-care method and for cardiac surgery. Advantages and disadvantages of these methods are discussed.
Available from: Joachim Stangier
- "e l s e v i e r . c o m / l o c a t e / t h r o m r e s Please cite this article as: Schmohl M, et al, Measurement of dabigatran plasma concentrations by calibrated thrombin clotting time in comparison to LC-MS/MS in human volunteers..., Thromb Res (2015), http://dx.doi.org/10.1016/j.thromres.2014.12.021 is a linear correlation between ECT and dabigatran plasma concentration, and the assay shows good sensitivity, its limited availability, the lack of standardisation and the lot-to-lot variability of reagents restrict its routine use in clinical practice  . Thrombin time (TT) also provides a direct measure of thrombin inhibition in a plasma sample and exhibits a linear dose–response relationship to dabigatran concentration. "
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ABSTRACT: Dabigatran etexilate is an oral direct thrombin inhibitor. Although routine anticoagulation monitoring with dabigatran is not usually required, a simple and precise laboratory test to measure dabigatran concentrations in patient plasma may be useful in certain clinical circumstances, such as emergency situations. The HEMOCLOT(®) Thrombin Inhibitors assay has demonstrated accurate and precise determination of dabigatran concentrations within a range of 50-500ng/ml. The objective of this study was to assess comparability of dabigatran concentrations determined by HEMOCLOT(®) and by liquid chromatography/tandem mass spectrometry (LC-MS/MS) in plasma samples from human volunteers with end-stage renal disease (ESRD) undergoing regular haemodialysis (HD) during a Phase I study.
Overall, 304 plasma samples were obtained from seven ESRD patients in dabigatran steady-state for measurement by HEMOCLOT(®) (calibrated diluted thrombin time [dTT]) and by LC-MS/MS. Agreement of dabigatran concentrations was assessed by regression analysis and difference plots.
The measurements of calibration standards of the HEMOCLOT(®) assay showed excellent precision with coefficients of variation <5%. Accuracy determined by analysis of two quality control samples was 90% and 111%. HEMOCLOT(®)-derived dabigatran plasma concentrations paralleled those obtained by LC-MS/MS. The mean ratio of the LC-MS/MS and dTT-derived concentrations was 0.955 (67% limits of agreement: 0.771-1.18).
The HEMOCLOT(®) Thrombin Inhibitors assay is suitable for measuring dabigatran plasma concentrations in volunteers with ESRD undergoing haemodialysis. The agreement between dabigatran concentrations determined by the HEMOCLOT(®) assay and the LC-MS/MS reference method met bioanalytical acceptance criteria.
Copyright © 2014. Published by Elsevier Ltd.
Thrombosis Research 01/2015; 135(3). DOI:10.1016/j.thromres.2014.12.021 · 2.45 Impact Factor
Available from: Heesun J. Rogers
- "The effect on TT is linear, but for monitoring near the therapeutic range, a diluted assay is necessary . The ecarin clotting time or chromogenic anti-IIa assays can also be used to quantitate DTI effect; however, these tests are not widely available [68, 78]. "
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ABSTRACT: Hypercoagulability can result from a variety of inherited and, more commonly, acquired conditions. Testing for the underlying cause of thrombosis in a patient is complicated both by the number and variety of clinical conditions that can cause hypercoagulability as well as the many potential assay interferences. Using an algorithmic approach to hypercoagulability testing provides the ability to tailor assay selection to the clinical scenario. It also reduces the number of unnecessary tests performed, saving cost and time, and preventing potential false results. New oral anticoagulants are powerful tools for managing hypercoagulable patients; however, their use introduces new challenges in terms of test interpretation and therapeutic monitoring. The coagulation laboratory plays an essential role in testing for and treating hypercoagulable states. The input of laboratory professionals is necessary to guide appropriate testing and synthesize interpretation of results.
Blood Research 06/2014; 49(2):85-94. DOI:10.5045/br.2014.49.2.85
Available from: Hossein Salmanizadeh
- "For measuring and confirming Ec crude venom coagulation activity, the PT test was conducted with different venom concentrations (Table 1). At lower concentrations, small clots are formed and coagulation time is longer, whereas at higher concentrations, larger clots are found and coagulation time is shorter . "
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ABSTRACT: The venom of the family Viperidae, including the saw-scaled viper, is rich in serine proteinases and metalloproteinases, which affect the nervous system, complementary system, blood coagulation, platelet aggregation and blood pressure. One of the most prominent effects of the snake venom of Echis carinatus (Ec) is its coagulation activity, used for killing prey.
Subfractions F1A and F1B were isolated from Ec crude venom by a combination of gel chromatography (Sephadex G-75) and ion exchange chromatography on a DEAE-Sepharose (DE-52). These subfractions were then intravenously (IV) injected into NIH male mice. Blood samples were taken before and after the administration of these subfractions. Times for prothrombin, partial thromboplastin and fibrinogen were recorded.
Comparison of the prothrombin time before and after F1A and F1B administrations showed that time for blood coagulation after injection is shorter than that of normal blood coagulation and also reduced coagulation time after Ec crude venom injection. This difference in coagulation time shows the intense coagulation activity of these subfractions that significantly increase the coagulation cascade rate and Causes to quick blood coagulation. The LD50 of the Ec crude venom was also determined to be 11.1 μg/mouse. Different crude venom doses were prepared with physiological serum and injected into four mice. Comparison of the prothrombin times after injection of subfractions F1A and F1B showed that the rate of mouse blood coagulation increases considerably. Comparing the partial thromboplastin times after injecting these subfractions with this normal test time showed that the activity rate of intrinsic blood coagulation system rose sharply in mice. Finally, by comparing the fibrinogen time after subfraction injections and normal test time, we can infer intense activation of coagulation cascade and fibrin production.
Journal of Venomous Animals and Toxins including Tropical Diseases 02/2013; 19(1):3. DOI:10.1186/1678-9199-19-3 · 0.80 Impact Factor
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