HAS-BLED Calculator

Enter your patient's clinical details — hypertension, renal/liver function, stroke history, bleeding history, labile INR, age, drugs, and alcohol use — and the HAS-BLED Calculator returns a total score with a corresponding major bleeding risk category for AF patients on anticoagulation. Each criterion is weighted to help clinicians identify patients who need closer monitoring after starting oral anticoagulants.

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

Hypertension (uncontrolled, sBP > 160 mmHg) *

Uncontrolled hypertension defined as systolic BP > 160 mmHg

Renal: dialysis, transplant, or creatinine ≥200 µmol/L. Liver: cirrhosis or bilirubin >2× normal with AST/ALT/ALP >3× normal. Each scores 1 point (max 2).

Stroke History *

Prior history of stroke, particularly lacunar

Prior Major Bleeding or Predisposition to Bleeding *

Includes bleeding history, anemia, or bleeding diathesis

Labile INR *

Unstable/high INR or time in therapeutic range <60% (applies to warfarin patients)

Age > 65 Years *

Patient age greater than 65 years

Drugs: antiplatelets, NSAIDs. Alcohol: ≥8 drinks/week. Each scores 1 point (max 2).

Results

HAS-BLED Score

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Bleeding Risk Category

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Estimated Bleeds per 100 Patient-Years

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Clinical Recommendation

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Results Table

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Frequently Asked Questions

What does the HAS-BLED score measure?

The HAS-BLED score estimates the 1-year risk of major bleeding in patients with atrial fibrillation who are being considered for or are already on oral anticoagulation. Major bleeding is defined as intracranial bleeding, hospitalization, a hemoglobin decrease of more than 2 g/L, and/or the need for blood transfusion. It was derived from a real-world cohort of 3,978 AF patients.

What does each letter in HAS-BLED stand for?

H = Hypertension (uncontrolled, sBP > 160 mmHg), A = Abnormal renal and/or liver function (1 point each), S = Stroke history, B = Bleeding history or predisposition, L = Labile INR, E = Elderly (age > 65), D = Drugs (antiplatelets, NSAIDs) and/or alcohol use (1 point each). The maximum possible score is 9.

What HAS-BLED score indicates high bleeding risk?

A score of 3 or higher is considered high risk. According to the original validation data, patients with a HAS-BLED score ≥ 3 have a meaningfully elevated rate of major bleeding (approximately 3.74 bleeds per 100 patient-years) and should undergo regular clinical review after starting oral anticoagulation. A score of 0–1 is low risk and 2 is intermediate risk.

Should a high HAS-BLED score lead to stopping anticoagulation?

No — a high HAS-BLED score should not automatically lead to withholding anticoagulation. Instead, it should prompt identification and correction of modifiable bleeding risk factors (e.g., controlling blood pressure, reviewing interacting drugs, reducing alcohol intake). For most AF patients, the stroke prevention benefit of anticoagulation still outweighs the bleeding risk.

Does labile INR apply to patients on NOACs?

The labile INR criterion was developed in the context of warfarin therapy, where time in therapeutic range (TTR) < 60% is considered labile. For patients on direct oral anticoagulants (DOACs/NOACs), this criterion is generally not applicable, and some clinical guidance suggests scoring it as 0 for NOAC patients.

What counts as abnormal renal function in HAS-BLED?

Abnormal renal function is defined as the presence of chronic dialysis, renal transplantation, or a serum creatinine level ≥ 200 µmol/L (approximately ≥ 2.3 mg/dL). Each of renal and liver dysfunction scores 1 point independently, so a patient with both conditions scores 2 points for this criterion.

What counts as abnormal liver function in HAS-BLED?

Abnormal liver function is defined as chronic hepatic disease (e.g., cirrhosis) or biochemical evidence of significant hepatic derangement — bilirubin > 2× the upper limit of normal combined with AST, ALT, or ALP > 3× the upper limit of normal. Like renal dysfunction, it adds 1 point to the HAS-BLED score.

Which drugs predispose to bleeding in the HAS-BLED score?

The 'D' criterion for drugs refers to concomitant use of antiplatelet agents (such as aspirin or clopidogrel) and/or non-steroidal anti-inflammatory drugs (NSAIDs). Alcohol use of 8 or more drinks per week also counts as a separate 1-point component under the same criterion letter, with a combined maximum of 2 points.