Medical AIHAS-BLED bleeding risk calculator
A simple bedside score (0 to 9) estimating the 1-year risk of major bleeding in atrial fibrillation patients on antithrombotic therapy. Its main value is highlighting reversible bleeding risk factors, not vetoing anticoagulation in patients who need it.
How to measure each input
- Hypertension
- The point reflects uncontrolled hypertension, taken as systolic blood pressure above 160 mmHg, which is itself a modifiable target.
- Abnormal renal function
- Chronic dialysis, renal transplant, or serum creatinine at or above 200 micromol/L (about 2.26 mg/dL). Counts independently of liver function.
- Abnormal liver function
- Cirrhosis or other chronic hepatic disease, or bilirubin more than twice the upper limit with transaminases or ALP more than three times the upper limit. Counts independently of renal function.
- Labile INR
- Applies to warfarin: unstable or supratherapeutic INRs, or time in therapeutic range below about 60%. Patients on a direct oral anticoagulant or not yet anticoagulated score 0 here.
- Drugs and alcohol
- Concurrent antiplatelet or NSAID use scores 1; alcohol intake of 8 or more units per week scores a separate 1, so these two together can add up to 2.
Interpretation
| Band | Meaning |
|---|---|
| 0 to 2, low bleeding risk | Relatively low annual major-bleeding risk (roughly 1 to 2% at a score of 0 to 1). Anticoagulation is generally well tolerated; continue and review modifiable factors at follow-up. |
| 3 or more, high bleeding risk | Higher annual major-bleeding risk (approximately 3.7% at 3, rising further at higher scores). This is a prompt to correct modifiable factors (blood pressure, NSAIDs/antiplatelets, alcohol, labile INR) and schedule closer review, not an absolute contraindication to anticoagulation. |
Pitfalls, exclusions and caveats
- HAS-BLED is designed to identify and correct modifiable bleeding risk, not to deny anticoagulation. Many high-score patients still derive net benefit once reversible factors are addressed.
- Several factors overlap with the stroke-risk score (age, hypertension, prior stroke), so a high HAS-BLED often accompanies a high CHA2DS2-VASc: the bleeding score should not simply cancel the stroke indication.
- The labile-INR criterion only applies to warfarin. Scoring it for a patient on a direct oral anticoagulant inflates the result.
- Thresholds (creatinine, bilirubin, blood pressure, alcohol units) are specific definitions from the derivation study; applying looser clinical impressions changes the score.
- It estimates major-bleeding probability over about one year and was derived in atrial fibrillation. Do not extrapolate it to unrelated anticoagulation settings.
1 point each: Hypertension (uncontrolled, SBP > 160 mmHg) + Abnormal renal function + Abnormal liver function + Stroke + Bleeding history or predisposition + Labile INR + Elderly (age > 65) + Drugs (antiplatelet / NSAID) + Alcohol (>= 8 units/week). Renal and liver count separately, as do drugs and alcohol. Total 0 to 9.HAS-BLED was described by Pisters et al. (2010). This implementation is an educational tool and is not affiliated with the original authors or any guideline body.
Frequently asked
Does a high HAS-BLED score mean I should stop anticoagulation?
No. A score of 3 or more flags elevated bleeding risk but is meant to trigger correction of modifiable factors (blood pressure, NSAIDs and antiplatelets, alcohol, labile INR) and closer follow-up. Most patients who need anticoagulation for stroke prevention still benefit from it.
Why can renal, liver, drugs, and alcohol each add separate points?
Abnormal renal and abnormal liver function score 1 each (up to 2 combined), and drug use and excess alcohol score 1 each (up to 2 combined). This is why the maximum is 9 rather than 7.
Should I count labile INR for a patient on a DOAC?
No. The labile-INR criterion only applies to warfarin or another vitamin K antagonist. Patients on a direct oral anticoagulant, or not yet anticoagulated, score 0 for that item.
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