Drug Monitoring of Argatroban Using the Ecarin Chromogenic Assay

ABSTRACT

The ecarin chromogenic assay (HaemoSys ECA; JenAffin GmbH, Jena, Germany) was developed for quantitative determination of direct thrombin inhibitors. As a further development of the ecarin clotting time (ECT), the ECA is based on the same principle of measurement: the activation of prothrombin by ecarin, a snake venom from Echis carinatus. In the ECA, the prothrombin activation products meizothrombin and meizothrombin-des-F1 cleave a chromogenic substrate. The activity of meizothrombin/meizothrombin-des-F1 is inhibited in a concentration-dependent manner by direct thrombin inhibitors. The ECA-T is an assay for quantitative determination of active site directed synthetic thrombin inhibitors. For argatroban ECA-T, there is a very precise and sensitive method of quantitative drug monitoring. Only very low interindividual variations were found compared with activated partial thromboplastin time and even ECT. ECA-T is independent of variations in prothrombin levels of the plasma samples. Heparin does not influence the measuring result. ECA-T is performed on manual coagulation analyzers with an option for optical measurement but can also be applied to automated laboratory systems. By the use of ECA-T as a drug-monitoring method, the drug safety of argatroban, most of all in critically ill patients, can be increased.

Argatroban - direct thrombin inhibitor - monitoring - ecarin chromogenic assay - ECA - ECA-T

REFERENCES

• 1 Nowak G, Bucha E. Quantitative determination of hirudin in blood and body fluids.  Semin Thromb Hemost. 1996;  22 197-202
• 2 Lange U, Nowak G, Bucha E. Ecarin chromogenic assay: a new method for quantitative determination of direct thrombin inhibitors like hirudin.  Pathophysiol Haemost Thromb. 2003/04;  33 184-191
• 3 Lange U, Olschewski A, Nowak G, Bucha E. Ecarin chromogenic assay.  Hamostaseologie. 2005;  25 293-300