Just scratching the surface: varied coagulation effects of polymer containers on TEG variables

Summary Background and objective: Different types of polymer surfaces affect the activation of platelets and coagulation pathway containers depending on their surface qualities. Importantly, this could produce variability of coagulation results obtained with thrombelastographical analysis. We assessed the effects of blood storage on thrombelastograph, TEG®, variables using polypropylene and polycarbonate containers. Methods: An in vitro experiment was performed, with eight volunteers in each limb. Fresh whole blood was stored in polypropylene or polycarbonate tubes prior to TEG® analysis, to assess the role of these plastics in the TEG® results obtained. Results: The polycarbonate tubes displayed slower onset of coagulation and greater variability of data for all four basic TEG variables (r-time, k-time, α-angle and maximum amplitude, P < 0.05). Polycarbonate results fell outside manufacturer reference ranges. Conclusions: It is likely that this is due to the altered surface properties and charge effects of the containers affecting proteins and platelets differently. Caution should be used in choosing which containers are used for storage of fresh blood prior to coagulation assessment, as variable results will follow where different types of plastic containers are employed.