Table 2.
| VHA | Test | Activator/Inhibitor | Significance |
|---|---|---|---|
| TEG | Kaolin | Kaolin, CaCl2 | Contact activation.; similar information as aPTT; isolates the intrinsic pathway. |
| rTEG® | Kaolin, TF, CaCl2 | Clotting is accelerated by activation of extrinsic TF and intrinsic kaolin pathways; contact activation; roughly analogous to an ACT; information about coagulation kinetics initiated via contact activation alone is lost. | |
| HTEG® | Kaolin, lyophilized heparinase, CaCl2 | Lyophilized heparinase neutralizes UFH; compared to kaolin TEG® to assess the heparin effect. | |
| MAff/CFF | Kaolin, TF, Abciximab, CaCl2 | Abciximab is a GPIIb/IIIa platelet receptor inhibitor that blocks the platelet contribution to clot formation; compared to kaolin TEG® to assess the fibrinogen contribution to clot strength independent of platelets. | |
| Native TEG® | Calcium | Native whole blood sample analyzed following recalcification only; impractical for clinical use given long R. | |
| ROTEM | INTEM | Ellagic acid, CaCl2 | Tests clotting activation through the intrinsic coagulation pathway, FXII, FXI, FIX, FVIII, FX, FV, FII, and fibrinogen; sensitive to the heparin effect; similar information as aPTT. |
| EXTEM | Recombinant TF, CaCl2, polybrene | Polybrene neutralizes UFH; tests clotting activation through the extrinsic coagulation pathway, FVII, FX, FV, FII, and fibrinogen. | |
| HEPTEM | Ellagic acid, CaCl2, lyophilized heparinase | Tests heparin and protamine sulfate effects in patients with high heparin concentration when compared with INTEM. | |
| FIBTEM | Recombinant TF, CaCl2, polybrene, cytochalasin D | Cytochalasin D blocks platelet activation; tests fibrinogen component contribution to clot stability; more sensitive to lysis. | |
| APTEM | Recombinant TF, CaCl2, polybrene, aprotinin/TXA | Tests fibrinolysis when performed together with the EXTEM. | |
| NATEM | CaCl2 | Native whole blood sample analyzed following recalcification only; impractical for clinical use given long CT. |
Abbreviations: activated clotting time (ACT); aprotinin thromboelastometry (APTEM); activated partial thromboplastin time (aPTT); clot formation time (CFT); clotting time (CT); extrinsic thromboelastometry (EXTEM); fibrin-based thromboelastometry (FIBTEM); heparin thromboelastometry (HEPTEM); intrinsic thromboelastometry (INTEM); TEG functional fibrinogen (MAff/CFF); non-activated thromboelastometry (NATEM); reaction time (R); rapid TEG® (rTEG®); rotational thromboelastometry (ROTEM®); thromboelastography (TEG®); tissue factor (TF); tranexamic acid (TXA); unfractionated heparin (UFH).