Determination of POC-ECT

For POC-ECT measurements we used DTM test cards, provided by Helena Laboratories, on a Cascade Abrazo analyzer. Underneath its transparent cover, the test card's reaction chamber contains ecarin, calcium, buffers, and (paramagnetic) iron oxide particles. When put into contact with a blood sample of approximately 30 µL, ecarin triggers a coagulation reaction by conversion of prothrombin into meizothrombin, which subsequently polymerizes fibrinogen into fibrin eventually leading to the formation of a stable clot. ⁸ An oscillating magnetic field under the card produced by the analyzer causes the iron particles to move constantly. The increasing restriction of movement caused by the forming fibrin clot is detected by an infrared optical system and reported as a clotting time. The presence of a thrombin inhibitor extends the clotting time proportionately to its concentration in the blood sample.