From the Guidelines
To read a rotational thromboelastometry (ROTEM) test, focus on the key parameters that assess different aspects of blood clotting, including clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), alpha angle, and maximum lysis (ML) parameter, as outlined in the systematic review of viscoelastic testing (TEG/ROTEM) in obstetrics and recommendations from the women's SSC of the ISTH 1. When interpreting ROTEM results, it's essential to understand the different assays and their purposes, such as INTEM, EXTEM, FIBTEM, and APTEM, which test specific pathways of coagulation 1.
- Key parameters to examine include:
- Clotting time (CT): measures how quickly clotting begins and reflects the initiation phase of coagulation
- Clot formation time (CFT): shows how rapidly a stable clot forms
- Maximum clot firmness (MCF): indicates the strength of the formed clot
- Alpha angle: represents the speed of clot formation
- Maximum lysis (ML) parameter: checks for signs of hyperfibrinolysis
- Comparing results across different ROTEM assays can help pinpoint specific deficiencies in coagulation pathways.
- Normal values vary by institution, so it's crucial to familiarize yourself with your laboratory's reference ranges. The use of ROTEM provides real-time visualization of clot formation and breakdown, making it valuable for guiding transfusion therapy and hemostatic management, particularly during major bleeding events or complex surgeries, as supported by the systematic review of viscoelastic testing (TEG/ROTEM) in obstetrics and recommendations from the women's SSC of the ISTH 1.
From the Research
Understanding ROTEm
To read ROTEm (Rotational Thromboelastometry), it's essential to understand the parameters and how they relate to coagulation management. ROTEm is a point-of-care viscoelastic assay that measures the kinetics of blood clotting [ 2 ]. The test provides information on the coagulation status of a patient, including the speed and strength of clot formation.
Key Parameters
- EXTEM (Extrinsic Activation Test): Measures the extrinsic coagulation pathway and provides information on the activity of coagulation factors [ 2 ].
- FIBTEM (Fibrin-based Test): Measures the fibrinogen level and clot firmness, providing information on the fibrinogen contribution to clot formation [ 2 ].
- MCF (Maximum Clot Firmness): Measures the maximum strength of the clot, which is an indicator of the overall coagulation status [ 3 ].
Interpretation
When interpreting ROTEm results, it's crucial to consider the clinical context and the patient's condition. For example, in major trauma patients, a low plasma fibrinogen concentration is a predictor of poor outcome [ 4 ]. In such cases, ROTEm-guided haemostatic therapy, with fibrinogen concentrate as first-line haemostatic therapy and additional prothrombin complex concentrate, can be an effective approach [ 3 ].
Clinical Applications
ROTem has various clinical applications, including:
- Trauma-induced coagulopathy: ROTEm can help guide the administration of fibrinogen concentrate and prothrombin complex concentrate in trauma patients [ 3 ].
- Cardiac surgery: ROTEm can be used to monitor coagulation status and guide the use of coagulation factor concentrates, such as fibrinogen and prothrombin complex concentrate [ 5 ].
- Massive bleeding: ROTEm can help identify the underlying coagulopathy and guide the use of targeted therapies, such as fibrinogen concentrate and prothrombin complex concentrate [ 6 ].