Table 3 Interpretation of coagulation tests with US Food and Drug Administration approved oral anticoagulants
From: Management of anticoagulant-related intracranial hemorrhage: an evidence-based review
Coagulation test | Factors evaluated | Interpretation with dabigatran | Interpretation with apixaban | Interpretation with rivaroxaban | Interpretation with warfarin |
|---|---|---|---|---|---|
PT | Factors II, V, VII, X, fibrinogen | Linear and dose dependent prolongation; at therapeutic range prolongs 1.2 times the basal value | Prolonged but not well studied or standardized | Linear and dose dependent prolongation; at therapeutic range prolongs 1.5 times the basal value | Prolonged |
aPTT | Factors II, V, VIII, IX, X, fibrinogen | Qualitative; prolongation dose dependent but not linear; at therapeutic range prolongs 2.5 times the basal value | Prolonged but not well studied or standardized | Linear and dose dependent prolongation; at therapeutic range prolongs 1.5 times the basal value; not as sensitive as PT | May be prolonged |
TT | Fibrinogen | Linear and dose dependent prolongation; but prolongation may be excessive and requires dilution of the plasma samples | Data not available | Not affected | Not affected |
ECT | Factor II | Linear and dose dependent prolongation; at therapeutic range prolongs three times the basal value | NA | NA | NA |
ETP | Factor II | Decreased – concentration dependent | Decreased – concentration dependent | Decreased – concentration dependent | NA |