The effects of delayed anticoagulation and use of evacuated vacuum tubes in the collection of whole blood for nonactivated thrombelastography (TEG) are not known.Objectives
The objective of this study was to examine the effects of delayed anticoagulation and use of vacuum-assisted blood collection tubes on results of nonactivated TEG.Methods
Twelve clinically healthy adult dogs were used in each of 3 studies. For each study, nonactivated TEG results from paired blood samples were compared. In study 1, the effect of delayed citrate anticoagulation was evaluated by collecting samples either into syringes containing citrate or into empty syringes followed by transfer to nonevacuated tubes containing citrate. In study 2, the effect of vacuum assistance in blood transfer was evaluated by collecting samples into syringes containing citrate and transferring either to nonevacuated plastic tubes or to evacuated plastic tubes. In study 3, the combined effects of delayed anticoagulation and vacuum assistance in blood transfer were evaluated by collecting samples into syringes containing citrate or into empty syringes followed by transfer to evacuated tubes containing citrate. Thrombelastographic analysis was performed in duplicate at 39°C after a 40-minute rest period.Results
The collection methods that delayed anticoagulation and/or used evacuated tubes yielded samples that appeared more coagulable compared with samples not exposed to delay or evacuated tubes.Conclusion
Methods by which samples are collected affect results of nonactivated TEG and should be considered when establishing reference intervals, interpreting results, and publishing TEG results.