Redefining haemostasis: Role of rotational thromboelastometry in critical care settings

Table 3 Rotational thromboelastometry delta/sigma and rotational thromboelastometry platelet assays

Assay	Activators and additives	Clinical significance
ROTEM delta/sigma
EXTEM	Calcium chloride + recombinant tissue factor + polybrene	Allow fast assessment of clot formation
		Explores the extrinsic coagulation pathway; VKAs; DOACs
		Increased values indicate need of PCC or FFP
		Not affected by aprotinin
		Sensitive to heparin
FIBTEM	Calcium chloride + recombinant tissue factor + polybrene + platelet inhibitor (cytochalasin D)	Depicts fibrin polymerization
		Assesses the contribution of fibrinogen to clot strength independent of platelets
		May also indicate XIII deficiency
		Used to calculate dose of fibrinogen concentrate or cryoprecipitate
APTEM	Calcium chloride + recombinant tissue factor + polybrene + aprotinin/tranexamic acid	Inhibition of premature lysis by addition of aprotinin/tranexamic acid
		In combination with EXTEM: (1) Rapid confirmation of fibrinolysis; (2) Verifying the effect of antifibrinolytic effect; and (3) Differential diagnosis of clot retraction and XIII deficiency
INTEM	Calcium chloride + ellagic acid	Assessment of clot formation and fibrin polymerization
		Explores the intrinsic coagulation pathway
		Increased values indicate need of FFP
HEPTEM	Calcium chloride + ellagic acid + heparinase	Testing in patients with very high heparin plasma concentrations
		In combination with INTEM
		To see UFH and protamine effects
NATEM	Calcium chloride	Expression of tissue factor on circulating cells, such as monocytes or cancerous cells
ECATEM	Calcium chloride + ecarin	Is sensitive for direct thrombin inhibitors (e.g., hirudin, argatroban, bivalirudin, dabigatran)
		Not sensitive to heparin
ROTEM platelet assays: These tests are used in patients treated with antiplatelet drugs or other medications that may affect platelet function, as well as in patients with suspected platelet dysfunction due to extracorporeal circulation, trauma, sepsis, or other reasons
ARATEM	Arachidonic acid	The platelets are activated with arachidonic acid to assess platelet function, particularly in patients treated with cyclooxygenase inhibitors such as acetylsalicylic acid
		Effects of CPB, trauma and sepsis on platelet function
ADPTEM	Adenosine di-phosphate	Platelets are activated using ADP to assess platelet function in patients treated with ADP receptor antagonists such as clopidogrel
		Effects of CPB, trauma and sepsis on platelet function
TRAPTEM	Thrombin receptor activating peptide-6	Platelets are activated using thrombin receptor activating peptide to evaluate platelet function in patients treated with PAR-1 receptor antagonists like vorapaxar or GP IIb/IIIa receptor antagonists such as abciximab
		Effects of CPB, trauma and sepsis on platelet function

ROTEM: Rotational thromboelastometry; DOACs: Direct oral anticoagulants; VKAs: Vitamin K antagonist; PCC: Prothrombin complex concentrate; FFP: Fresh frozen plasma; UFH: Unfractionated heparin; CPB: Cardiopulmonary bypass; ADP: Adenosine di-phosphate; PAR-1: Protease-activated receptor-1.