Factor inhibitor such as acquired hemophilia (D68.311)
Isolated prolonged aPTT
Mixing study fails to correct
Lupus anticoagulant
Prolonged aPTT without bleeding
Thrombosis history
Sample or lab artifact
Heparin contamination from line draw
Underfilled citrate tube
Past Medical History
Anticoagulation indications and history
Thromboembolic history
Atrial fibrillation (I48.91)
Venous thromboembolism history (I26.99, I82.409)
Mechanical heart valve (Z95.2)
Baseline organ function
Baseline physiology
Chronic kidney disease stage
Chronic liver disease severity
Prior bleeding
Prior bleeding events
Prior GI bleed
Prior intracranial hemorrhage
Physical Exam
General and vitals
General and hemodynamics
Appearance toxic or well
Orthostatic vital signs
Capillary refill and perfusion
Evidence of hypovolemia
Skin and mucosa
External bleeding signs
Petechiae
Ecchymoses
Oozing from sites
Oral mucosal bleeding
Neurologic
Neurologic exam
Mental status
Cranial nerves
Motor and sensory deficits
Gait when safe
Cardiopulmonary and abdomen
Internal bleeding clues
Tachycardia out of proportion
Abdominal tenderness or distension
Flank ecchymosis
Rectal exam when indicated
Lab Studies
Core labs for anticoagulation related abnormalities
Initial laboratory panel
CBC with platelets
PT and INR
aPTT
Fibrinogen
CMP with creatinine
Hepatic panel
Type and screen
Anticoagulant specific tests
Drug effect testing when available
Anti Xa level calibrated to heparin
Anti Xa level calibrated to apixaban or rivaroxaban if available
Thrombin time
Dilute thrombin time or ecarin clotting time for dabigatran if available
Interpretation pearls and pitfalls
Common interpretation pitfalls
INR does not quantify DOAC intensity reliably
aPTT may be normal with factor Xa inhibitors
Dabigatran often prolongs thrombin time markedly
Heparin contamination from line draw can falsely prolong aPTT
Mixing studies and inhibitors
Prolonged PT or aPTT diagnostic pathway
Mixing study correction suggests factor deficiency
Mixing study non correction suggests inhibitor
Factor VIII level and inhibitor assay if acquired hemophilia suspected
Imaging
Scoring Systems
Risk and bleeding scores
HAS BLED
ISTH major bleeding criteria
4T score for heparin induced thrombocytopenia
MRI
MRI indications
Suspected spinal epidural hematoma
Suspected intracranial pathology when CT nondiagnostic and stable
CT
CT indications
Noncontrast CT head for head trauma or neurologic symptoms
CT angiography or multiphase CT for suspected active GI bleeding local protocol dependent
CT abdomen and pelvis for suspected retroperitoneal bleed
Ultrasound
Ultrasound use
POCUS for free fluid when unstable
Bladder scan and renal ultrasound for hematuria evaluation when indicated
Special Tests
Hemostasis and transfusion adjuncts
Additional hemostasis tests
TEG or ROTEM if available for global clot assessment
Platelet function testing in selected antiplatelet cases local protocol dependent
Procedure related assessment
Bedside assessments
Stool guaiac limitations
Nasal and oral source evaluation for apparent hematemesis mimic
ECG
When relevant in bleeding or shock
ECG triggers
Hypotension or shock
Chest pain or dyspnea
Significant anemia suspected
ECG findings that change management
High risk findings
Ischemic ST changes
Rapid atrial fibrillation
QT prolongation with electrolyte derangements
Assessment
Problem representation
Anticoagulation related abnormal coagulation studies
Bleeding present or absent
Suspected agent class
Severity category
Severity stratification
Bleeding severity
Minor bleeding
Major bleeding
Life threatening bleeding
Diagnostic uncertainty
Alternate explanations for abnormal studies
Liver disease coagulopathy
DIC
Factor inhibitor
Lab artifact
Plan
Approach to the critical patient
First 5 minutes workflow
Cardiac and pulse oximetry monitoring
Two large bore IVs or IO if needed
Massive transfusion protocol activation if unstable bleeding
Type specific blood if immediate need
Anticoagulant holding and reversal decision
Reversal decision logic
Immediate reversal for life threatening bleeding
Immediate reversal for urgent surgery with high bleeding risk
No routine reversal for isolated lab abnormality without bleeding unless very high INR or procedure planned
Warfarin reversal
Warfarin management
Hold warfarin
Vitamin K PO 1 mg to 2.5 mg for elevated INR without bleeding local protocol dependent
Vitamin K IV 5 mg to 10 mg for major bleeding or urgent procedure
4 factor PCC for major bleeding
Dose per product and INR local protocol dependent
Fresh frozen plasma if PCC unavailable
Factor Xa inhibitor reversal
Apixaban and rivaroxaban reversal
Hold agent
Andexanet alfa for life threatening bleeding when available local protocol dependent
4 factor PCC 50 units per kg IV for life threatening bleeding when andexanet unavailable local protocol dependent
Activated charcoal if ingestion within 2 hours and airway protected
Dabigatran reversal
Dabigatran reversal
Hold agent
Idarucizumab 5 g IV total
Two consecutive 2.5 g doses
Hemodialysis for severe bleeding with renal failure when needed
Activated charcoal if ingestion within 2 hours and airway protected
Heparin and low molecular weight heparin reversal
Heparin reversal
Stop infusion
Protamine dosing
1 mg protamine per 100 units heparin given in prior 2 to 3 hours
Maximum single dose 50 mg
Enoxaparin reversal
Protamine 1 mg per 1 mg enoxaparin if within 8 hours
Protamine 0.5 mg per 1 mg enoxaparin if 8 to 12 hours
Transfusion and adjuncts
Blood product strategy
PRBC transfusion threshold individualized
Platelets for antiplatelet associated life threatening bleeding or thrombocytopenia per cause local protocol dependent
Fibrinogen replacement
Cryoprecipitate or fibrinogen concentrate to target at least 1.5 g/L in active bleeding
Consults and reassessment loop
Consultation plan
Hematology for complex coagulopathy or inhibitors
Gastroenterology for suspected GI bleeding
Neurosurgery for intracranial hemorrhage
Reassessment loop
Repeat vitals every 15 to 30 minutes until stable
Repeat hemoglobin at 4 to 6 hours or sooner if unstable
Repeat INR or drug relevant test after reversal when applicable
Disposition
Level of care criteria
ICU criteria
Hemodynamic instability
Ongoing major bleeding
Intracranial hemorrhage
Need for massive transfusion protocol
Admission and observation
Inpatient admission criteria
Major bleeding requiring transfusion or reversal
Suspected occult bleeding with dropping hemoglobin
Observation pathway criteria
Elevated INR treated with vitamin K without bleeding
Stable minor bleeding with reliable follow up
Discharge criteria
Discharge criteria
No ongoing bleeding
Stable hemoglobin when checked
Clear anticoagulant plan documented
Reliable follow up within 24 to 72 hours when INR or dosing change involved
Discharge Instructions
Copy discharge instructions
Patient instructions
Your blood clotting tests were abnormal while on blood thinner medication
Return to the emergency department right away for
New or worsening bleeding
Black stools or vomiting blood
Severe headache
New weakness or trouble speaking
Fainting or severe dizziness
Medication plan
Hold blood thinner as directed
Do not restart until instructed by your clinician
Avoid
NSAID pain medicines unless your clinician says it is safe
Alcohol binge drinking
Follow up
Anticoagulation clinic or prescriber within 24 to 72 hours
Repeat blood testing as arranged
References
Guidelines and core evidence
Key references
American College of Chest Physicians Antithrombotic Therapy Guidelines 2021
American Heart Association and American Stroke Association guideline on anticoagulant associated intracerebral hemorrhage latest update local protocol dependent
ISTH guidance on management of bleeding in patients on direct oral anticoagulants 2016 to 2022 updates local protocol dependent
American Society of Hematology guidelines on venous thromboembolism management and anticoagulation reversal 2018 to 2023 updates local protocol dependent
Andexanet alfa ANNEXA 4 study 2019
Idarucizumab RE VERSE AD study 2015
Source file
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.