In vitro testing of platelets using the thromboelastogram, platelet function analyzer, and the clot signature analyzer to predict the bleeding time

Background: Platelet aggregation, thromboxane A2 production and platelet annexin V binding are in vitro tests used to assess platelet function. This study was done to evaluate the clot signature analyzer (CSA), platelet function analyzer (PFA), and thromboelastogram (TE) as in vitro tests to predict the template bleeding time (BT). Study design and methods: Twelve normal volunteers were studied before and after removal of 2 units of RBC. Seven females were reinfused their RBC and 5 males were not. Samples were collected prior to and at 24, 48, and 72 h and 7 days after the RBC removal whether or not reinfusion of RBC was performed for measurement of TE, CSA, PFA and template BT. Results: BT increased significantly following the removal of 2 units of RBC and BT decreased significantly after the reinfusion of the 2 units of RBC in the 7 female volunteers. BT decreased during the 7-day period in the 5 male volunteers not reinfused their RBC. No significant correlations were observed between BT and platelet hemostatic time (PHT) and clotting time (CT) in the CSA and between the bleeding time and the closure time (CT) in the platelet function analyzer (PFA). Significant correlations were observed between BT and K time, the MA, and the angle recorded in the thromboelastogram. Conclusion: In this study in vitro testing using the clot signature analyzer, platelet function analyzer and the thromboelastogram could not be used to predict the template bleeding time. (c) 2006 Elsevier Ltd. All rights reserved.