HAS-BLED Calculator
Assess bleeding risk in atrial fibrillation patients on anticoagulation
HAS-BLED Risk Factors Assessment
Select "Yes" for any bleeding risk factors present in your patient. Each factor adds 1 point to the HAS-BLED score.
H - Hypertension
Systolic blood pressure > 160 mmHg (uncontrolled hypertension)
A - Abnormal Renal Function
Dialysis, transplant, or creatinine > 200 µmol/L (2.26 mg/dL)
S - Abnormal Liver Function
Cirrhosis or bilirubin > 2x ULN or AST/ALT/AP > 3x ULN
B - Bleeding History
Previous major bleeding or predisposition to bleeding
L - Labile INR
Time in therapeutic range < 60% (unstable/high INRs)
E - Elderly
Age ≥ 65 years
D - Drugs
Antiplatelet agents, NSAIDs, or other bleeding-predisposing drugs
S - Stroke History
Previous stroke or TIA
A - Alcohol Use
≥ 8 standard drinks per week
HAS-BLED Score Results
Annual Bleeding Risk
Clinical Recommendation
Consider anticoagulation therapy. Low bleeding risk.
Example Patient Case
Patient: 72-year-old with Atrial Fibrillation
Medical History: Hypertension (well-controlled), previous stroke
Current Medications: Taking aspirin daily
Age: 72 years (≥65)
Laboratory: Normal renal and liver function
Anticoagulation: Good INR control
HAS-BLED Score Calculation
H - Hypertension: No (well-controlled, SBP < 160)
A - Abnormal renal: No
S - Abnormal liver: No
B - Bleeding history: No
L - Labile INR: No
E - Elderly: Yes (+1 point)
D - Drugs: Yes (+1 point, aspirin)
S - Stroke: Yes (+1 point)
A - Alcohol: No
Total HAS-BLED Score: 3 (High Risk, 3.7% annual bleeding risk)
Risk Interpretation
Low Risk (0-1)
0.9-1.3% annual risk
Consider anticoagulation
Moderate Risk (2)
2.2% annual risk
Can consider with caution
High Risk (≥3)
3.7-8.7% annual risk
Consider alternatives
HAS-BLED Mnemonic
Major Bleeding Definition
Fatal bleeding
Clinically overt bleeding
Hb drop ≥20 g/L
≥2 units transfusion
Critical anatomic site
Understanding the HAS-BLED Score
Purpose and Application
The HAS-BLED score is a validated clinical tool designed to assess the 1-year major bleeding risk in patients with atrial fibrillation who are being considered for or are already on anticoagulation therapy.
Clinical Validation
Developed by Pisters et al. (2010), this score has been extensively validated and is recommended by international guidelines for bleeding risk assessment in AF patients.
Key Principles
Important Considerations:
- • Not meant to exclude patients from anticoagulation
- • Helps identify high-risk patients for closer monitoring
- • Focus on modifiable risk factors
- • Balance bleeding vs. stroke risk
Important: High bleeding risk should prompt consideration of reversible factors and enhanced monitoring, not automatic exclusion from anticoagulation.
Clinical Decision Making
Low Risk (0-1)
Proceed with anticoagulation as clinically indicated. Monitor according to standard protocols.
Moderate Risk (2)
Consider anticoagulation with enhanced monitoring. Address modifiable risk factors.
High Risk (≥3)
Carefully weigh risks vs benefits. Consider alternatives. Frequent monitoring and risk factor modification essential.
Risk Factor Modification Strategies
Modifiable Factors
- • Optimize BP control (target < 140/90)
- • Bleeding predisposition: Treat anemia, peptic ulcers
- • Labile INR: Improve anticoagulation management
- • Alcohol: Reduce or eliminate alcohol consumption
- • Drugs: Review and discontinue unnecessary bleeding-risk medications
Non-modifiable Factors
- • Age: Enhanced monitoring in elderly patients
- • Stroke history: Consider in risk-benefit analysis
- • Renal dysfunction: Dose adjustment may be needed
- • Liver disease: May affect anticoagulant metabolism
Related Atrial Fibrillation Risk Calculators
Important Medical Disclaimer
This HAS-BLED calculator is designed for educational purposes and clinical reference only. It should never replace comprehensive clinical assessment or professional medical judgment regarding anticoagulation therapy.
Healthcare professionals should:
- Use HAS-BLED as part of comprehensive atrial fibrillation management
- Balance bleeding risk with stroke risk (CHA2DS2-VASc score)
- Consider individual patient factors beyond the calculated score
- Follow current AF guidelines (ESC, AHA/ACC/HRS)
- Address modifiable bleeding risk factors when possible
- Never use high bleeding risk alone to exclude anticoagulation
This tool is based on the original HAS-BLED validation studies and should be used in conjunction with current evidence-based guidelines for atrial fibrillation management and anticoagulation therapy.