Practical approach to interpreting lab tests in the presence of DOACs
| Test . | Result . | Interpretation: is clinically significant anticoagulant effect present? . | |||
|---|---|---|---|---|---|
| Dabigatran . | Apixaban . | Rivaroxaban . | Edoxaban . | ||
| Routine coagulation tests - qualitative assessment . | |||||
| PT/INR | Normal | ← POSSIBLY PRESENT → | |||
| Abnormal | ← LIKELY PRESENT → | ||||
| aPTT | Normal | ← POSSIBLY PRESENT → | |||
| Abnormal | ← LIKELY PRESENT → | ||||
| Thrombin time | Normal | NOT PRESENT | ← Not relevant → | ||
| Abnormal | PRESENT | ||||
| Heparin or LMWH Anti-Xa assay | <0.1 IU/mL | Not relevant | ← LIKELY ABSENT → | ||
| >0.1 IU/mL | ← LIKELY PRESENT → | ||||
| Specialized DOAC assays—quantitative assessment | |||||
| Drug-specific quantitative assay | Concentration | dTT (Hemoclot®), ECT | Drug-specific anti-Xa activity assay | ||
| <50 ng/mL | ← LIKELY ABSENT → | ||||
| ≥50 ng/mL | ← LIKELY PRESENT → | ||||
| Test . | Result . | Interpretation: is clinically significant anticoagulant effect present? . | |||
|---|---|---|---|---|---|
| Dabigatran . | Apixaban . | Rivaroxaban . | Edoxaban . | ||
| Routine coagulation tests - qualitative assessment . | |||||
| PT/INR | Normal | ← POSSIBLY PRESENT → | |||
| Abnormal | ← LIKELY PRESENT → | ||||
| aPTT | Normal | ← POSSIBLY PRESENT → | |||
| Abnormal | ← LIKELY PRESENT → | ||||
| Thrombin time | Normal | NOT PRESENT | ← Not relevant → | ||
| Abnormal | PRESENT | ||||
| Heparin or LMWH Anti-Xa assay | <0.1 IU/mL | Not relevant | ← LIKELY ABSENT → | ||
| >0.1 IU/mL | ← LIKELY PRESENT → | ||||
| Specialized DOAC assays—quantitative assessment | |||||
| Drug-specific quantitative assay | Concentration | dTT (Hemoclot®), ECT | Drug-specific anti-Xa activity assay | ||
| <50 ng/mL | ← LIKELY ABSENT → | ||||
| ≥50 ng/mL | ← LIKELY PRESENT → | ||||
anti-Xa, anti-Xa activity assay; dTT, dilute thrombin time; ECT, ecarin clotting time.