Effect of pre-analytical conditions on the thrombodynamics assay.

ABSTRACT

INTRODUCTION: Standardization of pre-analytical conditions is the obligatory step for all potential diagnostic tests. Spatial clot growth (Thrombodynamics) is a new global hemostasis assay that considers spatial organization of coagulation. The principal parameter is rate of fibrin clot growth from the tissue-factor coated surface. In this work we studied the pre-analytical variables of Thrombodynamics assay that include conditions of blood collection, sample preparation and storage. MATERIALS AND METHODS: Blood of apparently healthy volunteers was used. Eight types of citrate blood collection tubes were tested, centrifugation conditions for plasma preparation were evaluated and impact of plasma freezing/thawing was tested. RESULTS: Among the blood collection tubes tested, BD Vacutainer glass tubes showed a significantly higher clot growth rate compared to plastic tubes. There was no difference between 3.2% and 3.8% of sodium citrate. For plasma preparation, a single 15 min centrifugation at 1,600 g shows significantly increased clot growth rate compared to plasma obtained by two sequential centrifugations (15 min 1 600 g, 5min 10,000 g). There was no significant difference between 1,600 g and 2,100 g if the second centrifugation was performed. For the second centrifugation there was no difference between 20 min at 1 600 g and 5 min at 10,000g. Frozen-thawed plasma showed increased clot growth rate compared to fresh plasma. CONCLUSION: The data represent the necessary steps for the standardization of Thrombodynamics assay and for the formulation of the operating guide.