The effects of pneumatic tube system transport on ROTEM analysis and contact activation assessed by thrombin generation test

Thromboelastometry (ROTEM) is a popular point-of-care test. It generates results quickly and may benefit individualised guided haemostatic therapy. However, processing of specimens by non-technicians might decrease the quality and reproducibility of results. Centralised laboratory equipment receiving specimens through a pneumatic tube system (PTS) could avoid this. This study aimed to evaluate the influence of PTS transport on ROTEM results and its contribution to contact activation assessed by thrombin generation (TG).

Methods: Specimens from 44 patients were drawn immediately after arterial puncture. Two were anticoagulated by citrate and two by citrate/corn trypsin inhibitor, a Factor XIIa pathway inhibitor. Both types of samples were transported by walking and PTS. Subsequently, analysis was performed: ROTEM on citrated blood, and TG on citrated and corn trypsin inhibitor (CTI) blood using either 0 or 1 pM tissue factor (TF).

Results: In ROTEM analysis the NATEM assay showed significant differences. The EXTEM assay revealed small significant differences for clot formation time: 65 seconds (SD ± 20) versus 67 seconds (SD ± 17), and alpha angle 79° (SD ± 3) versus 77° (SD ± 3). The results remained within reference range. TG was not significantly affected by the type of tube transport, independent of the amount of TF.

Conclusion: PTS for ROTEM analysis is feasible except for NATEM assays. The amount of contact activation via Factor XIIa in terms of TG is independent of transport type. However, due to the different characteristics of pneumatic systems, hospitals should check its impact on the results before introducing this route of transport.