PB1049 - ROTEM Thromboelastometry System- Caution in interpretation

Background: Rotational Thromboelastometry (ROTEM) is a method to measure the viscoelastic properties of blood clot. The ROTEM INTEM, EXTEM, FIBTEM and APTEM are four different assays that measure the clotting and fibrinolysis of whole blood samples.

Aims: ROTEM has to be interpreted by personnel who have knowledge and relevant experience. We highlight here the importance of taking a stepwise approach with essential clinical information and rest of the lab parameters if available.

Methods: EXTEM A5 and FIBTEM A5 are the clot amplitudes at 5 minutes after the start of the test in the EXTEM and FIBTEM assays respectively. EXTEM A5 is the combined contribution of fibrinogen and platelets to the clot strength, while FIBTEM A5 reflects the contribution of fibrinogen alone. The difference between EXTEM A5 and FIBTEM A5 indicates the platelet function. These parameters can be used as early indicators of hypofibrinogenemia and thrombocytopenia, which are common causes of coagulopathy.

Results: Figure 4a shows a ROTEM result of a bleeding patient that has EXTEM A5 value below 35 mm and FIBTEM A5 value below 9 mm. Based on the A-5 algorithm, this indicates that the patient requires the administration of fibrinogen concentrate or cryoprecipitate. Figure 4b shows a normal ROTEM results of a bleeding patient which indicates no significant coagulopathy or fibrinolysis detected. Figure 4c shows a ROTEM result of a bleeding patient that has a EXTEM A5 value above 35 mm and a contradictory FIBTEM A5 value of 2 mm

Conclusion(s): The ROTEM assay is an essential tool that provides information on the patient’s coagulation status, which is useful in managing patients with acute bleeding. It can help avoid inappropriate administration of blood products to patients. Wrong interpretation however can lead to mismanagement and undesirable patient outcomes. Hence, we recommend regular training and appraisal for staff involved in using ROTEM.