HAS-BLED Calculator

The patient is in the low risk group

Are you suffering from atrial fibrillation and want to know about bleeding tendencies? This HAS-BLED calculator is specially designed to calculate one-year bleeding risk for patients with atrial fibrillation. It depends on multiple factors to accurately evaluate the bleeding risk. Before this HAS-BLED calculator, a more complex, algorithm-based, HEMORR²HAGES was used to assess the bleeding risk. This calculator was more difficult to use. So, the HAS-BLED calculator gained popularity because of its easy use.

The HAS-BLED calculator was originally manuscript in 2010. This calculator was derived from a cohort study of 3978 patients suffering from atrial fibrillation. This patient population also includes such patients who are on oral anticoagulants, antiplatelets, or antithrombotic agents to depress the normal coagulation process. By following all such factors, this calculator helps to assess the 1-year risk in patients with atrial fibrillation.

This article summarizes all important details relevant to the HAS-BLED calculator and the usage pattern of this calculator. In addition, it also provides details about atrial fibrillation and major bleeding factors to understand the details of the HAS-BLED calculator properly.

What is atrial fibrillation?

Atrial fibrillation is a condition in which abnormal electrical conduction starts suddenly in the atria leading to a highly irregular heartbeat. This abnormal conduction can overstimulate the heart’s natural pacemaker, losing control of the heart rhythm.

The exact cause is still unknown. But, the most common causes of atrial fibrillation are growing age, coronary artery disease, cardiovascular problems, high blood pressure, physical stress, or other heart-related problems.

The typical symptoms of atrial fibrillation include:

  • Fast, fluttering, or pounding heartbeat sensation
  • Chest pain or discomfort
  • Fatigue or tiredness
  • Lightheadedness or dizziness
  • Unable to exercise
  • Shortness of breath
  • Feeling of weakness

What do you understand about the term bleeding or major bleeding?

The HAS-BLED calculator is used to assess the major bleeding risk for patients with atrial fibrillation. Major bleeding is defined as

  • Intracranial bleeding
  • A hemoglobin decline to 2g/dL
  • Bleeding that requires hospitalization
  • Fatal bleeding
  • Overt bleeding
  • Bleeding that requires the blood transfusion of at least two blood units
  • Bleeding involving a crucial anatomical part of the body

How can we use the HAS-BLED calculator?

With growing age, doctors are more commonly facing a huge amount of patients suffering from atrial fibrillation. The only management for such patients is to optimize the risk factors. The major risk factors are as follows:

  • Risk for stroke
  • Thromboprophylaxis
  • Fatal bleeding

Due to these life-threatening risk factors, there are multiple diagnostic and therapeutic scales to take proper decisions and medication. You can assess the stroke risk with our CHA2DS2-VASC calculator. Whereas, for bleeding risk, doctors prioritize going for a HAS-BLED calculator.

There are multiple factors associated with the HAS-BLED calculator to whom you need to answer in ‘yes’ or ‘no’. If you go for a ‘no’ option, the associated question with that factor will automatically be excluded for your ease. In the following section, we’ll properly illustrate the HAS-BLED criteria to clear your queries and concepts. In addition, you can also use this HAS-BLED calculator before the anticoagulation therapy for atrial fibrillation patients. In this way, this HAS-BLED calculator also helps to identify the patients with high bleeding risk to manage them with more care. For patients with high bleeding risk, it is better to consider medication with reversible bleeding risk factors.

HAS-BLED score criteria

The HAS-BLED calculator follows HAS-BLED criteria to assign a proper score for a patient. It consists of nine main factors to evaluate and calculate bleeding risk for patients with atrial fibrillation. Those nine factors are as follows:

  1. High blood pressure or hypertension – it is defined as blood pressure exceeding the limit of 140/90 mmHg. It counts for a point in a has-bled calculator if the systolic blood pressure is more than 160 mmHg. Arterial blood pressure is not the concern here but overall blood pressure is. Uncontrolled or untreated blood pressure is a serious concern for patients with atrial fibrillation.
  2. Abnormal kidney function – if the patient is an option for a kidney transplant, has chronic dialysis, or has a creatinine level of more than 200 μmol/L and decreased glomerular filtration rate.
  3. Abnormal liver function – it is explained as the patients with liver cirrhosis or chemical indicators more than the upper normal limit. For example:
  4. Bilirubin is greater than 2 times the upper normal limit.
  5. AST/ASP/AP levels are three times more than the upper normal limit.
  1. Previous stroke history – does the patient previously have a stroke history?
  2. Bleeding risk – did the patient previously have any major bleeding or bleeding tendency like anemia or decreased hemoglobin level?
  3. Labile INR – it is defined as if the patient is taking anticoagulants and the INR is at least 40% of the therapeutic time range.
  4. Elder patients – are the patients 65 years old or more than that?
  5. Alcohol intake – it describes the ingestion of 8 standard drinks per week.
  6. Drugs – it is defined as if the patient is on such drugs that can increase the risk of bleeding. These drugs usually include antiplatelet therapy or NSAIDs.

How to interpret the score for the HAS-BLED calculator?

Following the HAS-BLED criteria, every factor holds one point. If the patient is having higher scores, it means the patient is at high bleeding risk. The main purpose of this HAS-BLED calculator is to differentiate the patients with high bleeding risk. It is important to know these patients prior to the anticoagulation therapy. As anticoagulation therapy can further increase the risk of major bleeding. This measuring scale provides a score for an individual person and a proper assessment regarding the clinical picture of the patient.

Point score:Risk group:Management plan:
0 points:Low bleeding riskAnticoagulation therapy
1 to 2 pointsIntermediate bleeding riskAnticoagulation therapy
≥ 3 points High bleeding risk – consider any alternative management protocol other than anticoagulation therapyMonitor the patient carefully and regularly. Monitor INR frequently. Take actions to maintain reversible factors.

The potentially reversible factors are those which can be improved or reversed. Doctors must take these points into consideration to properly evaluate the patient. The list of potentially reversible factors includes

  • Hypertension
  • Labile INR
  • Predisposition to bleeding (treating underlying problems like anemia)
  • Alcohol intake
  • Drugs management


The HAS-BLED calculator is used to assess one-year bleeding risk for the patients with atrial fibrillation. The common medication for atrial fibrillation may include antiplatelet or anticoagulation therapy, including warfarin. These drugs can increase the risk of bleeding in a normal patient. For these reasons, physicians prefer to assess the bleeding risk prior to the usage of anticoagulation therapy. If the patient is lying between low to moderate bleeding risk, your doctor may start anticoagulation therapy. But, if you are at high bleeding risk, your doctor may go for any other treatment plan.

The prime purpose of this HAS-BLED calculator is to scrutinize the patients with high bleeding risk to properly manage them according to the requirements. Go through the details of this article to completely grab the information related to the HAS-BLED calculator.

Frequently asked questions (FAQs)

What are the specific limits of a HAS-BLED calculator?

The HAS-BLED calculator can only be used for patients with atrial fibrillation who require management in the form of anticoagulation therapy. So, it is important to know the bleeding risk for such patients. The HAS-BLED calculator evaluates the bleeding risk for such patients.

What do you understand by the HAS-BLED score of 1?

As we mentioned in the article, there are three divisions of the bleeding risk. A patient with a 1 score indicates a moderate or intermediate-level bleeding risk for the patients.

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