CHADS2 score is based on a point system in which 2 points are assigned for a history of stroke or transient ischemic attack and 1 point each is assigned for age equal to or greater more than 75 years, hypertension, diabetes, or clinical heart failure or impaired left ventricular systolic function (generally interpreted as an ejection fraction ≤ 40%).

The CHA2DS2-VASc risk score is based on a point system in which 2 points are assigned for a history of stroke or TIA, or age ≥75; and 1 point each is assigned for age 65-74 years, a hypertension, diabetes, cardiac failure, vascular disease and female sex. On the basis of the risk strata defined in previous guidelines, a CHA2DS2-VASc score of 0 corresponds to "low risk", a score of 1 corresponds to "intermediate risk", and a score of 2 or more corresponds to "high risk".

The HAS-BLED score is based on a point system in which 1 point is assigned for hypertension (systolic blood pressure >160 mmHg), 1 point for each of abnormal renal (presence of chronic dialysis or renal transplantation or serum creatinine ≥200 μmol/L) and liver (chronic hepatic disease or biochemical evidence of significant hepatic derangement) function, 1 point each is assigned for stroke, bleeding (previous bleeding history and/or predisposition to bleeding), labile Internation Normalized Ratios (INRs,unstable/high INRs or poor time in therapeutic range), age >65 years and 1 point each for drugs (such as antiplatelet agents, non-steroidal anti-inflammatory drugs) or alcohol.