We would like to thank Kozek-Langenecker et al for their letter and welcome their comments as they clearly have far greater experience in the use of thromboelastography than we do. The intention of our 'head-to-head' [1] was a direct comparison of basic information about both commercially available thromboelastographs, the ROTEM® and the TEG®. These machines are not interchangeable, with different mechanisms of action, activators and significant differences in trace results [2]. The service from the manufacturer in terms of training and reliable aftersales support was also afforded important consideration.

The ‘dedicated local customer service’ that the Austrian team received may reflect the fact that the headquarters of the company supplying the ROTEM are based in Munich, Germany, and that over the last 18 years strong links with their distributer have been developed. In the UK, TEG has a long established distributer and service provider (Haemoscope TEG®) but at the time of our comparison there was a changeover period between UK distributers for the ROTEM. However, equipment and training were provided directly from the parent company for the comparison, and communication/support from the new UK distributer (Pentapharm) has so far been exemplary. 

In answer to Kozek-Langenecker’s specific questions: comparison of costs was kept to basic tests only, hence the omission of costs for the functional fibrinogen. The functional fibrinogen test for the TEG has been commercially available in the UK/Eire since January 2008 and when tested, we found the TEG had a warm up time of less than 5 min, corresponding with the published data.

The TEG may be used for assessing a patients’ current anticoagulant state as antiXa blood levels > 0.1U.ml^-1 are seen as a hypocoagulable TEG clotting pattern [3, 4]. In an urgent situation when laboratory antiXa assays are unavailable, a TEG may be a helpful adjunct to determining a parturient’s risk of bleeding during surgery/delivery.

There is no substitute for experience, and ‘discussion with experienced users’ is always useful, but in the UK few institutions have equal experience with both devices and there are no published direct comparisons of ease of use, local support/training and relevant costs. Differences in access to resources are highlighted by the fact that we are still unable to purchase either machine, whereas Kozek-Langnecker et al have used both ‘simultaneously for some years’.

K.J. Ashpole, S.M. Yentis, G. Jackson

References

1.       Jackson G, Ashpole K, Yentis S. The TEG vs the ROTEM thromboelastography / thromboelastometry systems. Anaesthesia 2009; 64: 212-5.

2.      Nielson VG. A comparison of the Thromboelastograph and the ROTEM. Blood Coagulation and Fibrinolysis 2007, 18:

3.      Backe SK, Lyons GR. High-dose tinzaparin in pregnancy and the need for urgent delivery. British Journal of Anaesthesia 2002; 89: 331-4.

4.      Klein SM, Slaughter TF, Vail PT et al. Thromboelastography as a Perioperative measure of anticoagulation resulting from low molecular weight heparin: A comparison with Anti-Xa concentrations. Anesthesia and Analgesia 2000; 91: 1091-5.