Coagulation Profile
ABCs
- look for → bleeding, thrombosis, hemodynamic instability
- check vitals → tachycardia, tachypnea, oxygen desaturation
- always interpret in clinical context
- pre-op · anticoagulation · active bleeding · suspected PE/DVT
pattern recognition
| pattern | PT | aPTT | normal range | common causes |
|---|---|---|---|---|
| PT ↑ only | ↑ | normal | PT 11–15 s · INR 0.9–1.1 | warfarin, early vitamin K deficiency, liver disease, factor VII deficiency |
| aPTT ↑ only | normal | ↑ | 25–40 s | heparin, hemophilia (FVIII / IX), lupus anticoagulant, von Willebrand disease |
| both ↑ | ↑ | ↑ | — | DIC, severe liver disease, severe vitamin K deficiency, anticoagulants |
| D-dimer | — | — | — | DVT, PE, DIC (high sensitivity); also ↑ in infection, malignancy, pregnancy, post-op |
anticoagulant effects
| drug | PT | aPTT |
|---|---|---|
| warfarin | ↑ | ± |
| heparin (UFH) | — | ↑ |
| LMWH | — | ± |
| DOACs | ± | ± |
management
if bleeding
- hold anticoagulants · call senior
- send → CBC, coag profile, group & cross
- vitamin K (if warfarin) or PCC / FFP (if significant bleeding)
reversal agents
| anticoagulant | antidote | dose | notes |
|---|---|---|---|
| warfarin | vitamin K | 10 mg IV (slow) | always give if bleeding |
| warfarin · major | 4-factor PCC | 1500–2000 units IV | rapid reversal · preferred |
| warfarin · alt | FFP | 2–4 units IV | if PCC unavailable · watch overload |
| heparin (UFH) | protamine sulfate | 1 mg / 100 units (max 50 mg) | give slowly (hypotension) |
| LMWH | protamine (partial) | 1 mg / 1 mg enoxaparin | ~60% reversal only |
| DOACs | 4-factor PCC | 2000 units IV (25–50 u/kg) | if major bleeding |
| all | tranexamic acid | 1 g IV | adjunct · supportive only |
if no bleeding
- don’t panic — look for the cause (anticoagulants, liver disease, sepsis)
- adjust meds if needed
escalate
- active bleeding · suspected DIC · unexplained + worsening labs · clinical deterioration
studying for the IM exam? the IM Rapid Review covers this in the same format. see the sample chapter.
Last reviewed · May 2026