HAS-BLED Calculator

What Is the HAS-BLED Score?

HAS-BLED estimates one-year major bleeding risk in patients with atrial fibrillation who may receive anticoagulation. It flags modifiable bleeding risk factors rather than excluding patients from therapy. Pair it with stroke risk tools such as the CHA2DS2-VASc Calculator when balancing thromboembolic and bleeding risks.

The Nine HAS-BLED Criteria

Each present criterion adds one point: uncontrolled hypertension (SBP above 160 mmHg), abnormal renal function, abnormal liver function, prior stroke, prior major bleeding, labile INR on warfarin, age 65 or older, alcohol use of at least 8 drinks per week, and concomitant drugs that increase bleeding (antiplatelets or NSAIDs).

Interpreting the Total Score

A score of 0 indicates low bleeding risk (about 0.9% annual major bleeding, roughly 1.1 events per 100 patient-years). Scores of 1 to 2 suggest moderate risk where anticoagulation may still be reasonable. Scores of 3 or higher indicate high risk and warrant closer follow-up, INR monitoring when applicable, and correction of reversible factors.

Clinical Use

HAS-BLED should be calculated before starting anticoagulation. High scores do not automatically contraindicate therapy when stroke risk is substantial. Instead, they prompt vigilance and interventions on reversible items such as blood pressure control, alcohol reduction, and medication review.