🩸 Coagulation Test Interpretation
Interpret PT/aPTT combinations, the mixing study, DIC and platelet considerations. Browser-side reference.
Isolated PT rise: VII deficiency, early warfarin/vitamin K deficiency, liver disease.
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When to use
Localise a coagulation abnormality to the intrinsic, extrinsic or common pathway and separate deficiency from inhibitor.
How it works
PT = extrinsic/common; aPTT = intrinsic/common. Mixing study: corrects = deficiency, does not correct = inhibitor.
Key points
- Isolated PT rise: VII deficiency, early warfarin/vitamin K deficiency, liver disease.
- Isolated aPTT rise: haemophilia, vWD, heparin, lupus anticoagulant.
- DIC: low fibrinogen, high D-dimer, low platelets, prolonged PT/aPTT.
- Normal PT/aPTT with bleeding: consider platelet/vessel disorder, XIII deficiency, mild vWD.
References
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| View | PT/aPTT combinations |
|---|
→InterpretationPT/aPTT combinations
- PT ↑ aPTT normal：Extrinsic: factor VII deficiency, early vitamin K deficiency/warfarin, liver disease
- aPTT ↑ PT normal：Intrinsic: VIII/IX/XI (haemophilia), vWD, heparin, lupus anticoagulant
- PT ↑ aPTT ↑：Common pathway: late vitamin K deficiency, DIC, liver disease, severe fibrinogen ↓
| View | DIC / platelets |
|---|
→InterpretationDIC / platelets
- DIC：Fibrinogen ↓, D-dimer ↑, platelets ↓, PT/aPTT ↑ (use a dynamic + scoring approach)
- Platelets：< 150 thrombocytopenia; both count and function (drugs/uraemia) affect bleeding
Frequently asked questions
- What is Coagulation Test Interpretation?
- Interpret PT/aPTT combinations, the mixing study, DIC and platelet considerations. Browser-side reference.
- How is Coagulation Test Interpretation calculated? What is the core formula?
- PT = extrinsic/common; aPTT = intrinsic/common. Mixing study: corrects = deficiency, does not correct = inhibitor.
- When is Coagulation Test Interpretation used?
- Localise a coagulation abnormality to the intrinsic, extrinsic or common pathway and separate deficiency from inhibitor.
- What are the key clinical points for Coagulation Test Interpretation?
- Isolated PT rise: VII deficiency, early warfarin/vitamin K deficiency, liver disease. Isolated aPTT rise: haemophilia, vWD, heparin, lupus anticoagulant. DIC: low fibrinogen, high D-dimer, low platelets, prolonged PT/aPTT. Normal PT/aPTT with bleeding: consider platelet/vessel disorder, XIII deficiency, mild vWD.
- What are the limits and cautions when using Coagulation Test Interpretation?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Coagulation Test Interpretation calculated in practice? Can you show a worked example?
- Inputs: View PT/aPTT combinations → Result: Interpretation PT/aPTT combinations（PT ↑ aPTT normal: Extrinsic: factor VII deficiency, early vitamin K deficiency/warfarin, liver disease, aPTT ↑ PT normal: Intrinsic: VIII/IX/XI (haemophilia), vWD, heparin, lupus anticoagulant, PT ↑ aPTT ↑: Common pathway: late vitamin K deficiency, DIC, liver disease, severe fibrinogen ↓） Inputs: View DIC / platelets → Result: Interpretation DIC / platelets（DIC: Fibrinogen ↓, D-dimer ↑, platelets ↓, PT/aPTT ↑ (use a dynamic + scoring approach), Platelets: < 150 thrombocytopenia; both count and function (drugs/uraemia) affect bleeding）