LA assays
| Types of LA assay/principle | Assays | Non-LA causes of clotting time prolongation |
|---|---|---|
| Based on the intrinsic pathway | LA-sensitive routine aPTT Dilute activated partial thromboplastin time (dAPTT) Kaolin clotting time (KCT) Silica clotting time (SCT) | Isolated or combined deficiencies of coagulation factors II, V, VIII, IX, X, XI, XII, prekallikrein (PK), and high molecular weight kininogen (HMWK) Fibrinogen deficiencies Non-phospholipid-dependent inhibitors Therapeutic anticoagulation with vitamin K antagonist (VKA), unfractionated heparin (UFH), low molecular weight heparin (LMWH), direct thrombin inhibitor (DTI), and direct FXa inhibitor (DFXaI) |
| Based on the extrinsic pathway | Dilute prothrombin time (dPT) Activated Seven Lupus Anticoagulant (ASLA) assay | Isolated or combined deficiencies of coagulation factors II, V, X; also factor VII for dPT Fibrinogen deficiencies Non-phospholipid-dependent inhibitors Therapeutic anticoagulation with VKA, DTI, and DFXaI Therapeutic anticoagulation with UFH & LMWH if neutraliser capacity exceeded |
| Based on the common pathway (FX activation) | dRVVT Vipera lebetina venom time (VLVT) | Isolated or combined deficiencies of coagulation factors II, V, and X Fibrinogen deficiencies Non-phospholipid-dependent inhibitors Therapeutic anticoagulation with VKA, DTI, and DFXaI Therapeutic anticoagulation with UFH & LMWH if neutraliser capacity exceeded |
| Based on the common pathway (FII activation) | Taipan snake venom time (TSVT) Textarin time | Factor II deficiency; also factor V for textarin time Fibrinogen deficiencies Non-phospholipid-dependent inhibitors Therapeutic anticoagulation with UFH, LMWH, and DTI |