Bleeding risk with AFib
HAS-BLED score calculator
HAS-BLED is the bleeding risk score clinicians use for people with atrial fibrillation (AFib) who take, or are thinking about, a blood thinner (anticoagulant). It counts risk factors for major bleeding, many of which can be treated or changed.
Which of these apply to you?
For people diagnosed with AFib. Some items need lab results or your care team's records. Nothing you enter leaves this page.
What you will see
Your HAS-BLED score from 0 to 9, its level, and which of your items can often be treated or changed.
Educational only, not medical advice. Never start, stop or skip a blood thinner on your own.
Source
Pisters R et al., Chest 2010 (the original score). Item definitions and levels as printed in the 2023 ACC/AHA/ACCP/HRS atrial fibrillation guideline.
Validated in
Created in 3,978 people with atrial fibrillation in the Euro Heart Survey who were followed for 1 year; 53 (1.5%) had a major bleed.
Limits
Only for people with AFib. It estimates bleeding risk, not stroke risk, and it does not weigh the benefit of a blood thinner. The 2023 guideline says it should not be used on its own to decide whether someone takes an anticoagulant.
What a high score means, and what it does not
The 2023 US atrial fibrillation guideline from the American College of Cardiology, American Heart Association, American College of Clinical Pharmacy and Heart Rhythm Society says people with AFib should be checked for factors that raise bleeding risk, such as past bleeding and medicines that increase bleeding, so those factors can be addressed (ACC/AHA 2023). It also says that in people at high risk of stroke, bleeding risk scores should not be used on their own to decide whether to take an anticoagulant, but to find and change bleeding risk factors and to inform the decision (ACC/AHA 2023).
Many HAS-BLED items, such as age, high blood pressure and a past stroke, also raise the risk of stroke, so people with a high bleeding score often have a high stroke risk too (ACC/AHA 2023). The guideline notes that population studies suggest the benefits of a blood thinner for stroke prevention generally outweigh the bleeding risk, even in people judged to be at high bleeding risk (ACC/AHA 2023).
General safety advice (not part of the guideline): never stop, skip or change a blood thinner because of this score. Talk to the clinician who prescribes it.
The items
| Letter | Item | Points |
|---|---|---|
| H | Uncontrolled high blood pressure: systolic over 160 mm Hg | 1 |
| A | Abnormal kidney function (dialysis, kidney transplant or serum creatinine over 2.26 mg/dL) or abnormal liver function (cirrhosis, or bilirubin over 2 times the upper limit of normal with ALT, AST or alkaline phosphatase over 3 times normal) | 1 each, up to 2 |
| S | Stroke, from bleeding or a clot | 1 |
| B | Bleeding history or a tendency to bleed | 1 |
| L | Labile INR: time in the target range under 60% (for people on warfarin) | 1 |
| E | Elderly: age 65 or older | 1 |
| D | Drugs (antiplatelet medicines or NSAIDs) or excessive alcohol use (8 or more units a week) | 1 each, up to 2 |
Source: the 2023 guideline's scoring note (ACC/AHA 2023), based on Pisters 2010 (Pisters 2010). One difference: the original paper gives the age point for being older than 65 (Pisters 2010), while the 2023 guideline gives it at age 65 or older (ACC/AHA 2023). This calculator follows the guideline, so a 65-year-old gets the point here but would not in the original score. The guideline groups scores as low (0), moderate (1 to 2) and high (3 or more) (ACC/AHA 2023).
Where the score comes from
HAS-BLED was built from 3,978 people with AFib in the Euro Heart Survey to estimate the 1-year risk of major bleeding: bleeding inside the skull, bleeding that led to a hospital stay, a drop in hemoglobin or a transfusion (Pisters 2010). The bleeding rate rose as risk factors added up, and the score's accuracy (C statistic) was 0.72 in the full group (Pisters 2010).
Later studies found that HAS-BLED and similar bleeding scores separate people who bleed from people who do not only modestly; a French nationwide study found a C index of 0.58 to 0.59 (ACC/AHA 2023). That is one reason the guideline uses these scores to spot fixable risks rather than to decide treatment (ACC/AHA 2023).
Common questions
I do not take warfarin. What about the INR item?
Labile INR is defined by time in the target range on warfarin (ACC/AHA 2023). If you do not take warfarin, leave it unticked.
Should I stop my aspirin or pain reliever?
Not on your own. The guideline lists medicines that increase bleeding as one of the factors to review (ACC/AHA 2023), and the person who prescribes your blood thinner can tell you whether a change makes sense.
When is bleeding an emergency?
General safety advice (not part of the guideline): call 911 for bleeding that will not stop, vomiting blood, black or bloody stools, or a sudden severe headache while on a blood thinner.
After a TIA (mini-stroke), see the ABCD2 score. For stroke risk with AFib, see CHA2DS2-VASc explained and the stroke risk check. Not diagnosed with AFib? See the atrial fibrillation screening check. To check your blood pressure readings, see blood pressure ranges.
Sources
- Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJ, Lip GY. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest. 2010;138(5):1093-1100. doi.org/10.1378/chest.10-0134
- Joglar JA, Chung MK, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. J Am Coll Cardiol. 2024;83(1):109-279. doi.org/10.1016/j.jacc.2023.08.017
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-31. Spotted an error? See About.