Variables Influencing the Thrombostat 4000: Recommended Standardization

Abstract

The in vitro bleeding test (IVBT) (Thrombostat 4000) was performed on blood samples from healthy blood donors using a “preliminary standard test.” Only one factor of the test procedure was changed each time.We found the following parameters to have a significant influence on the test results: time interval between sampling and testing, diameter of the filter's aperture, capillary diameter, aggregating agents and their concentration, temperature of the blood and cartridges, method of drying the capillaries, the aspiration pressure, and the hematocrit of the blood sample. According to our data, we propose a standard IVBT for routine application and modifications for special diagnostic use.

Are In-Vitro Platelet Function Tests Useful in Predicting Blood Loss Following Open Heart Surgery?

“…Importa nt mec ha nism s of the haem ostati c dam age by ECC such as fibrin olysis have no effect on the results obta ined w ith th e PFA-100~or th e Hepconv HMS. Moreover, haematocrit, platelet count, and leukocyte count we re show n to influen ce clos ure tim es of th e Throm bostat 4000" ( 14,15), an invitro bleeding tes t sim ilar to the PFA-100", Thus it see ms reasonable to assume that these haematological parame ters may also influence th e results of the P FA-10 0~, Anothe r aspect is the pos tope rative treatme nt of patients, since this may influence total blood loss from che st drains. The type of infusion for postoperative vo lume replacem ent and retransfusion of s hed media stinal blood may affect haerno staris (16, 17), but shed media stinal blood was not retransfused in this study and no heta starch infusion s were give n.…”

Influence of ABO blood groups on primary hemostasis

“…Primary nonvascular hemostasis can be investigated by this method. With an automated system (Thrombostat 4000, [TST] VDG, Seeon, Germany), the principle of the IVBT was turned into a practical application 18–23 . A further development of this method has recently become available with a platelet function analyzer (PFA‐100 [PFA] Dade Behring, Marburg, Germany) 24,25 .…”

3. Internationales Symposium: „Autologe Transfusion - Von der Euphorie zur Ratio: Praktisches Handeln aus wissenschaftlicher Sicht” (Teil III)Does Hemodilution Enhance Coagulability?

“…The negative effect of hemodilution on primary hemostasis cannot be explained with the lower platelet concentration, since platelets never fell below 100.000/l which is the threshold value for physiological platelet function in the PFA-100 [14]. Earlier in-vitro studies have shown that hemodilution significantly reduces primary hemostasis in PFA even when platelet concentration remained unchanged [15]. Different dilution solutions had different effect [16].…”