From the Guidelines
To read a ROTEM test, focus on key parameters such as clotting time (CT), clot formation time (CFT), alpha angle, maximum clot firmness (MCF), and lysis indices, and consider the specific ROTEM assays used, including EXTEM, INTEM, FIBTEM, APTEM, and HEPTEM, as recommended by the most recent study 1. When interpreting ROTEM results, it is essential to compare them to reference ranges and consider the clinical context, as prolonged CT may suggest coagulation factor deficiencies, extended CFT may indicate poor clot formation, reduced MCF may point to platelet or fibrinogen issues, and increased lysis indices may suggest hyperfibrinolysis 1. The FIBTEM test is particularly useful in assessing fibrinogen contribution to clot formation, and its parameters, such as A5 and A15, have been shown to correlate significantly with fibrinogen levels 1. In the context of postpartum hemorrhage (PPH), ROTEM has been used to guide transfusion therapy, with FIBTEM A5 being a useful predictor of the need for transfusion of at least 4 units of red blood cells and 8 units of allogeneic products 1. Some key points to consider when reading a ROTEM test include:
- EXTEM evaluates the extrinsic pathway
- INTEM evaluates the intrinsic pathway
- FIBTEM assesses fibrinogen contribution
- APTEM detects hyperfibrinolysis
- HEPTEM measures heparin effect
- Prolonged CT suggests coagulation factor deficiencies
- Extended CFT indicates poor clot formation
- Reduced MCF points to platelet or fibrinogen issues
- Increased lysis indices suggest hyperfibrinolysis
- FIBTEM A5 is a useful predictor of the need for transfusion in PPH It is also important to note that ROTEM has limitations, such as not being able to assess the contribution of endothelium to coagulation or detect von Willebrand disease, and not being sensitive to antiplatelet agents or platelet inhibition 1. Overall, ROTEM provides a rapid, point-of-care assessment of coagulation status, allowing for targeted blood product administration and monitoring of hemostatic therapy effectiveness, as supported by the most recent and highest quality study 1.
From the Research
Understanding ROTEM Results
To read ROTEM (Rotational Thromboelastometry) results, it's essential to understand the different tests and parameters involved. ROTEM provides a graphical and numerical representation of induced hemostasis in whole blood samples, allowing for the assessment of the state of hemostasis [ 2 ].
ROTEM Tests and Parameters
The main ROTEM tests include:
- INTEM (intrinsically activated test)
- EXTEM (extrinsically activated test)
- FIBTEM (fibrin-based extrinsically activated test)
- APTEM (extrinsically activated test with the addition of aprotinin to inhibit fibrinolysis) Key parameters to consider when interpreting ROTEM results include:
- Clotting time (CT)
- Clot formation time (CFT)
- Maximum clot firmness (MCF)
- Alpha-angle (α-angle)
- Clot amplitude (CA) and lysis index (LI)
Interpreting ROTEM Results
When interpreting ROTEM results, consider the following:
- Abnormal EXTEM and FIBTEM clot amplitude (CA5, CA10) or maximal clot firmness (MCF) may diagnose coagulopathy and predict blood transfusion and mortality [ 3 ].
- Presence of hyperfibrinolysis by ROTEM is associated with increased mortality [ 3 ].
- FIBTEM assay is useful for assessing fibrinogen activity, and fibrinogen replacement therapy is recommended at an MCF of FIBTEM < 10 mm and FIBTEM A10 < 7 mm [ 2 ].
Clinical Application of ROTEM Results
ROTEM-guided bleeding management algorithms can effectively reduce the number of transfusions, healthcare costs, and complications, leading to improved patient safety and overall health [ 2 ]. Evidence-based algorithms for rotational thromboelastometry-guided bleeding management are essential for linking ROTEM testing and hemostatic interventions [ 4 ].
Key Considerations
- ROTEM results should be interpreted in conjunction with clinical judgment and other laboratory tests [ 5 ].
- The implementation of ROTEM in patient blood management requires adequate technical and interpretation training, education, and logistics, as well as interdisciplinary communication and collaboration [ 4 ].