1,329 calculators and references across 60 specialties, with each tool type shown up front.
SGLT2 Benefit Probability Score: Explanation and Clinical Context The SGLT2 Benefit Probability Score is designed to estimate the likelihood of clinical benefit from SGLT2 inhibitors in patients with heart failure (HF), chronic kidney disease (CKD), and/or diabetes mellitus (DM). This tool incorporates key clinical variables such as age, presence of HF, CKD, and DM. Higher scores indicate a greater predicted benefit
Shanghai Score for Brugada Syndrome: Explanation and Clinical Context The Shanghai Score is a diagnostic scoring system developed to assess the likelihood of Brugada Syndrome based on clinical, electrocardiographic, familial, and genetic criteria. It assigns weighted points to spontaneous Type 1 ECG, fever-induced or drug-provoked Type 1 ECG, documented ventricular arrhythmias, family history of sudden cardiac death,
SHARE-FI (Frailty Index in Elderly Cardiac Patients): Explanation and Clinical Context SHARE-FI is a validated tool designed to assess frailty in community-dwelling older adults, particularly useful in elderly cardiac patients. It uses five domains: exhaustion, loss of appetite, weakness (grip strength), slowness (walking speed), and low physical activity. Each domain contributes to a composite score that classifies
: Rationale, Model Choices, and Clinical Context This calculator estimates relative cardiometabolic risk multipliers associated with shift work using pooled quantitative effects from large meta-analyses. For cardiovascular disease (CVD) outcomes, a contemporary dose–response meta-analysis showed that night-shift workers have a higher risk of total CVD events (RR ≈ 1.13) and CVD mortality (RR ≈ 1.27); risk rises with
Shock Index (HR/SBP Ratio): Explanation and Clinical Context The Shock Index (SI) is a simple, bedside physiological ratio calculated by dividing the heart rate (HR) by the systolic blood pressure (SBP). It serves as a rapid and sensitive indicator of hemodynamic compromise and circulatory shock. A normal Shock Index typically ranges from 0.5 to 0.7. Values above 0.9 are considered abnormal and have been strongly cor
SHOCK Score: Explanation and Clinical Context The SHOCK Score was developed from the SHOCK Trial Registry to predict short-term mortality among patients presenting with cardiogenic shock following acute myocardial infarction. This score integrates seven readily available clinical variables: age > 75 years, female gender, anterior myocardial infarction, previous MI, serum creatinine > 1.9 mg/dL, altered mental status,
SHOCKED Score: Explanation and Clinical Context The SHOCKED Score is a clinical tool developed to predict long-term survival in patients with implantable cardioverter-defibrillators (ICDs). It incorporates several clinical variables to stratify patients into different risk categories. A higher score indicates a higher risk of mortality, guiding clinicians in decision-making regarding device therapy and management str
Explanation and Clinical Context This tool is designed for patients with acute coronary syndromes who have undergone percutaneous coronary intervention with contemporary drug eluting stents and are treated with dual antiplatelet therapy that combines aspirin and an oral P2Y12 inhibitor. The 2025 acute coronary syndromes guideline identifies a default strategy of about 12 months of dual antiplatelet therapy in patient
Short Nutritional Assessment Questionnaire (SNAQ): Explanation and Clinical Context SNAQ is a validated screening tool to quickly assess the risk of malnutrition in adults, especially elderly patients or those with chronic illness. It evaluates three key parameters: appetite loss, recent unintentional weight loss, and use of supplemental drinks or tube feeding. Each response is scored, and the total SNAQ score indica
Shunt Fraction Index (Qp:Qs Ratio): Explanation and Clinical Context The Qp:Qs ratio, also known as the Shunt Fraction Index, is used to quantify the magnitude of left-to-right cardiac shunts. It is defined as the ratio of pulmonary blood flow (Qp) to systemic blood flow (Qs). A Qp:Qs ratio of 1 indicates no shunt, while values above 1 indicate a left-to-right shunt, with higher values reflecting larger shunts. Clini
Signal-Averaged QRS Duration: Explanation and Clinical Context Signal-Averaged QRS (SA-QRS) duration is a specialized ECG measurement designed to detect subtle conduction abnormalities that predispose patients to ventricular arrhythmias. It is typically performed using high-resolution ECG recordings and computer averaging to reduce noise. Normal SA-QRS duration is generally less than 114 ms. Values between 114–120 ms
Clinical reference for Simon Broome Criteria Familial Hypercholesterolemia FH Calculator, with practical context for use alongside current guidance and professional judgment.
Simpson’s biplane method: explanation, clinical context and references The biplane method of disks (the modified Simpson’s rule) estimates left ventricular end-diastolic and end-systolic volumes from apical 4-chamber and apical 2-ch views; the ejection fraction (LVEF) is then calculated as EF = [(EDV − ESV) / EDV] × 100%. In routine practice the machine may report volumes from each apical view and clinicians commonly
Single Antiplatelet Therapy Transition for High Bleeding Risk: Explanation and Clinical Context Transition from dual antiplatelet therapy to single antiplatelet therapy is supported in the management of high bleeding risk patients after percutaneous coronary intervention according to the AHA ACS Guideline 2025. For patients with elevated bleeding tendency a shorter DAPT duration is reasonable and may safely reduce he
Single Sample hs Troponin Evaluation ≥3 Hours Symptom: Explanation and Clinical Context High sensitivity cardiac troponin is the preferred biomarker for evaluating suspected acute coronary syndrome. AHA 2025 guideline states that hs Troponin allows earlier rule out or rule in of myocardial infarction. When evaluating a patient who presents at least three hours from symptom onset a single hs Troponin below the assay s
Temperature Celsius Heart Rate bpm Respiratory Rate PaCO2 mmHg White Blood Cell Count x10⁹ per L Band Form Percentage Explanation and Clinical Context SIRS describes a widespread inflammatory response of the body to internal or external stressors. It is defined by abnormalities in temperature heart rate respiratory rate PaCO2 and white blood cell count including increased immature neutrophil band forms. The criteria
SITS-ICH Score: Explanation and Clinical Context The SITS-ICH Score is a validated clinical tool designed to predict the risk of symptomatic intracranial hemorrhage (sICH) following intravenous thrombolysis with alteplase in patients with acute ischemic stroke. Developed from the SITS-MOST registry, it uses baseline demographic and clinical variables to provide an individualized estimate of hemorrhagic risk. The scor
Siu Predictive Model: Explanation and Clinical Context The Siu Predictive Model estimates the risk of maternal cardiac events during pregnancy in women with pre-existing heart disease. It incorporates key clinical predictors: NYHA functional class III–IV, history of heart failure, presence of left heart obstruction, and previous cardiac events. Each predictor is assigned a weight, and the sum produces a total score t
Six CIT Dementia Screening Tool Explanation and Clinical Context The Six CIT Dementia Screening Tool offers a brief cognitive assessment that is practical for primary care settings. It evaluates orientation, working memory, and attention using six simple tasks that can be administered rapidly without the need for special equipment. The scoring system assigns weighted values to each item, creating a total score range
SLEDAI Lupus Activity Score Explanation and Clinical Context SLEDAI is a validated global index used to quantify disease activity in patients with systemic lupus erythematosus. It evaluates clinical and laboratory findings that reflect inflammatory activity over the preceding ten days. The score incorporates neurological involvement renal manifestations mucocutaneous changes musculoskeletal signs serologic activity a
SLUMS Cognitive Test Explanation and Clinical Context The Saint Louis University Mental Status Examination is a cognitive screening tool used to identify early cognitive decline and neurocognitive disorders. It evaluates multiple domains that include orientation memory attention executive function visuospatial ability and delayed recall. The test is sensitive for detecting mild neurocognitive disorder which may not b
— explanation and clinical context This tool classifies heart failure patients into subpopulations using commonly accepted left ventricular ejection fraction thresholds (HFrEF <41%, HFmrEF 41–49%, HFpEF ≥50%). It then provides directional prognostic information using two well-known validated frameworks as proxies: the MAGGIC risk framework for 1- and 3-year mortality, and the GWTG-HF model for in-hospital mortality r
Smoking Cessation Cardiac Event Reduction Model: Explanation and Clinical Context Smokers who quit experience a rapid decline in cardiovascular risk within the first few years, with heavy smokers (≥20 pack-years) achieving approximately a 39% lower risk of incident cardiovascular disease by 5 years compared with those who continue to smoke (hazard ratio ~0.61). Risk continues to decline more gradually over the follow
Clinical reference for Socioeconomic Deprivation Cardiac Risk Adjustment Index Sd Crai Calculator, with practical context for use alongside current guidance and professional judgment.
Sodium Correction in Hyperglycemia Explanation and Clinical Context Sodium correction in the setting of hyperglycemia is essential because elevated serum glucose increases plasma osmolality and shifts water from the intracellular compartment into the extracellular compartment. This movement dilutes serum sodium and leads to a factitious reduction in the measured value. Correcting sodium helps clinicians assess the tr
SOFA (Sepsis-related Organ Failure Assessment): Explanation and Clinical Context The SOFA score quantifies the degree of dysfunction across six organ systems (respiratory, coagulation, hepatic, cardiovascular, neurologic, and renal) by assigning 0–4 points for each organ system, producing a total score ranging from 0 to 24. It was developed primarily as an objective tool to describe and track organ dysfunction in cri
SOFA Score for Organ Dysfunction Explanation and Clinical Context The Sequential Organ Failure Assessment score is a clinical tool that evaluates the severity of organ dysfunction across six major organ systems. These systems include respiration coagulation liver function cardiovascular status central nervous system and renal function. Each system receives a subscore between zero and four based on objective clinical
SOLOIST-WHF Post-HF Benefit Index: Explanation and Clinical Context The SOLOIST-WHF (Sotagliflozin on Cardiovascular Events in Patients with Type 2 Diabetes and Worsening Heart Failure) trial was a landmark study evaluating the dual SGLT1/2 inhibitor sotagliflozin in patients recently hospitalized for acute decompensated heart failure, with or without reduced ejection fraction. This calculator estimates the relative
sPESI (Simplified Pulmonary Embolism Severity Index): Explanation and Clinical Context The sPESI is a validated scoring tool designed to stratify the 30-day mortality risk of patients diagnosed with acute pulmonary embolism (PE). It simplifies the original PESI by including six clinical variables: age >80 years, history of cancer, history of chronic cardiopulmonary disease, heart rate >110 bpm, systolic blood pressur
Spleen Injury Grading Scale Explanation and Clinical Context The Spleen Injury Grading Scale provides a structured method for classifying splenic trauma using imaging based anatomical criteria. This system helps clinicians understand the severity of parenchymal disruption hematoma size vessel involvement and the extent of devascularization. Grade I reflects minor injury with limited subcapsular hematoma or shallow la
Spot Urine Sodium Response Score: Explanation and Clinical Context The Spot Urine Sodium Response Score (SUNSS) is a clinical tool designed to predict the likelihood of poor diuretic response in patients with acute decompensated heart failure (ADHF). It incorporates key variables that influence natriuretic response: age, systolic blood pressure, serum sodium, and spot urine sodium. Lower urine sodium indicates reduce
SPRINT Trial Risk Stratification: Explanation and Clinical Context The SPRINT Trial (Systolic Blood Pressure Intervention Trial) risk stratification is a clinical tool designed to estimate the expected benefit and risk of intensive (<120 mmHg) versus standard (<140 mmHg) systolic blood pressure control in patients with hypertension. It incorporates age, chronic kidney disease (CKD) status, and estimated 10-year ASCVD
SSN (Suprasternal Notch) SSN (Suprasternal Notch) Ao : Aorta, LA : Left atrium, LLpvn : Left lower pulmonary vein, LUpvn : Left upper pulmonary vein, RLpvn : Right lower pulmonary vein, RUpvn : Right upper pulmonary vein, SVC : Superior vena cava. SSN View (Left Innominate Vein, SVC, Right PA) Ao : Aorta, L innom vn : Left innominate vein, PA : Pulmonary artery, RPA : Right pulmonary artery, SSN : Suprasternal notch,
ST2 Biomarker Risk Tier: Explanation and Clinical Context The soluble ST2 (sST2) is a member of the interleukin-1 receptor family and acts as a biomarker of myocardial stress and fibrosis. It is a strong prognostic marker in patients with heart failure and acute coronary syndromes, independently predicting mortality and heart failure readmission. Risk tiers are generally classified based on sST2 concentration: - <35
STABLE Score (TEVAR Risk): Explanation and Clinical Context STABLE Score is a validated tool to predict 30-day mortality in patients undergoing thoracic endovascular aortic repair (TEVAR) for acute complicated type B aortic dissection. It incorporates four key clinical factors: Shock at presentation, presence of Malperfusion, Age >70 years, and Previous Aortic Surgery. Each factor scores 1 point if present, and the t
STAT Mortality Categories: Explanation and Clinical Context The STAT Mortality Categories are a validated risk stratification tool designed to estimate perioperative mortality for pediatric and congenital cardiac surgery. Patients are categorized from STAT 1 (lowest risk) to STAT 5 (highest risk) based on the complexity of the surgical procedure. STAT 1 procedures have the lowest predicted mortality (~0.7–2%), wherea
STAT Mortality Categories (STS–EACTS): Explanation and clinical context The STAT (Society of Thoracic Surgeons – European Association for Cardio-Thoracic Surgery) Mortality Scores and Categories are an empirically derived, procedure-based stratification system for congenital and pediatric cardiac surgery. Each index operation is assigned a numeric STAT score (range ~0.1–5.0) derived from large STS/EACTS registry data
Explanation and Clinical Context This tool supports bedside decisions about how urgent reperfusion should be in patients with suspected ST segment elevation myocardial infarction and which reperfusion strategy is most appropriate in a given clinical setting. It uses simple inputs that mirror key elements of the 2025 guideline for acute coronary syndromes including the type of hospital time from symptom onset to first
This tool converts the dose of a selected glucocorticoid to the equivalent dose of another glucocorticoid based on established relative anti inflammatory potency. Steroid Dose Conversion Explanation and Clinical Context Glucocorticoids vary in anti inflammatory potency mineralocorticoid activity and biological half life so dose conversion is required to maintain therapeutic equivalence when switching agents. Hydrocor
Steroid-Dependence Risk Score for (Recurrent) Pericarditis: Explanation and Clinical Context This scoring tool is derived from a prognostic model of patients with recurrent pericarditis that included steroid-dependence among its key variables (age, sex, number of recurrences, etiology, heart rate, pericardial imaging, LVEF, colchicine use, steroid use, DMARD use). The intention is to stratify patients by risk of poor
STOP-AF Risk Index: Explanation and Clinical Context The STOP-AF Risk Index is a proposed clinical risk stratification tool designed to estimate the likelihood of developing atrial fibrillation (AF) in patients without prior AF, based on key clinical and echocardiographic parameters (such as age, prior atrial arrhythmia episodes, left atrial diameter, and presence of sleep apnea). The aim is to identify higher‐risk i
: Explanation and Clinical Context The STOPDAPT-2 ACS trial evaluated an abbreviated dual antiplatelet therapy (DAPT) strategy (1–2 months followed by clopidogrel monotherapy) versus standard 12-month DAPT in patients with acute coronary syndrome undergoing successful percutaneous coronary intervention. Although the primary endpoint did not demonstrate non-inferiority for the abbreviated therapy regarding the composi
Age (years) Acute coronary syndrome (ACS) presentation? Select Yes No High-bleeding-risk (HBR) criteria met? Select Yes No Complex PCI (yes/no)? Select Yes No STOPDAPT-2 ACS Risk Subgroup Calculator: Explanation and Clinical Context The STOPDAPT-2 family of trials investigated the safety and efficacy of abbreviated dual antiplatelet therapy (DAPT) duration followed by P2Y12 inhibitor monotherapy versus standard 12-mo
Stress Test versus Coronary Computed Tomography Before Discharge Pathway Tool Explanation and Clinical Context In contemporary management of acute coronary syndromes the two thousand twenty five guideline from the American College of Cardiology and the American Heart Association notes that selected patients can safely undergo either noninvasive stress testing or coronary computed tomography angiography before hospita
Stroke Prognostic Instrument II (SPI-II): Explanation and Clinical Context The Stroke Prognostic Instrument II (SPI-II) is a validated clinical scoring system designed to predict the risk of recurrent stroke or major vascular events (such as myocardial infarction or vascular death) in patients with a prior non-cardioembolic ischemic stroke. SPI-II was developed from the National Institute of Neurological Disorders an
: Explanation and Clinical Context The ABCD2 score estimates early stroke risk after a transient ischemic attack (TIA) based on five clinical variables: age ≥ 60 years (1), blood pressure ≥ 140/90 mmHg (1), clinical features (unilateral weakness 2; speech disturbance without weakness 1), symptom duration (≥ 60 minutes 2; 10–59 minutes 1), and diabetes (1). Total 0–7. Risk stratification: Low (0–3), Moderate (4–5), Hi
Stroke Volume: Explanation and Clinical Context Stroke volume represents the amount of blood ejected by the left ventricle during each cardiac contraction. The most accurate non invasive method for calculating stroke volume in clinical practice uses pulsed wave Doppler at the left ventricular outflow tract. The calculation requires the cross sectional area of the outflow tract and the velocity time integral of the sy
Stroke Volume Index (SVi): Explanation and Clinical Context Stroke Volume Index is a hemodynamic parameter that describes the amount of blood ejected by the left ventricle during each cardiac contraction, adjusted to body surface area. This index refines the interpretation of stroke volume by incorporating patient size, making it a more accurate indicator of forward flow in individuals with significantly different bo
Stroke Volume Index (SVi) for RV Failure Prediction: Explanation and Clinical Context Stroke Volume Index (SVi) is a hemodynamic parameter that represents the stroke volume normalized to body surface area. It is calculated as cardiac output divided by heart rate and then indexed to BSA, providing a load-adjusted measure of cardiac performance. In the context of right ventricular (RV) failure prediction, SVi has been
STRONG-HF Risk Framework — explanation and clinical context this calculator uses a transparent research model points system that aggregates commonly reported prognostic features relevant to patients hospitalized for acute heart failure (age, hemodynamics at discharge, NT-proBNP, renal function, potassium, LVEF, recent HF hospitalization, and intensity of guideline-directed medical therapy achieved at discharge). It
STS Adult Cardiac Surgery Risk Score: Explanation and Clinical Context The STS Adult Cardiac Surgery Risk Score provides an evidence-based estimation of perioperative mortality and morbidity in adults undergoing cardiac surgery. It incorporates patient-specific clinical variables such as age, sex, renal function, history of heart failure, previous cardiac surgery, and type of surgical procedure. The score is derived
STS CABG Mortality Risk Score: Explanation and Clinical Context The STS CABG Mortality Risk Score is a validated tool used to estimate the risk of operative mortality for patients undergoing coronary artery bypass grafting (CABG). It incorporates various clinical variables, including patient demographics, comorbidities, and procedural factors, to provide a personalized risk assessment. This score aids clinicians in d
— explanation and clinical context The STS Congenital Heart Surgery Database (CHSD) mortality risk approach stratifies operative risk primarily by procedure complexity (the STAT mortality category) and then adjusts for multiple patient-level factors (age group, weight/low birthweight, prior cardiothoracic operations, genetic/chromosomal abnormalities, non-cardiac congenital anomalies, multiple preoperative risk facto
STS Primary Mitral Valve Repair/Replacement Risk Calculator: Explanation and Clinical Context The STS Primary Mitral Valve Repair/Replacement Risk Calculator is a tool developed by The Society of Thoracic Surgeons to estimate the short-term (operative/30-day) risk associated with mitral valve repair or replacement surgeries for patients with primary mitral regurgitation (MR) and degenerative mitral etiology. This cal
STS Risk Score (SAVR): Explanation and Clinical Context The STS Risk Score is a validated tool developed by the Society of Thoracic Surgeons to estimate the risk of operative mortality and major morbidity for patients undergoing surgical aortic valve replacement (SAVR). It incorporates patient demographics, comorbidities, laboratory values, and procedural factors to produce a probability of 30-day or in-hospital mort
STS Score (Aortic/Mitral/Combined): Explanation and Clinical Context The Society of Thoracic Surgeons (STS) risk score is a validated tool to predict operative mortality and morbidity for patients undergoing cardiac surgery, including aortic valve replacement, mitral valve surgery, or combined procedures. The score incorporates multiple patient-specific variables such as age, sex, NYHA class, left ventricular ejectio
STS-IE Surgical Risk Model: Explanation and Clinical Context The STS-IE (Society of Thoracic Surgeons – Isolated Valve Surgery) Risk Model is a validated tool to predict postoperative mortality and major morbidity for patients undergoing isolated valve surgery. It uses patient-specific clinical variables including age, sex, previous cardiac surgery, NYHA functional class, left ventricular ejection fraction, diabetes,
Sudden Cardiac Death (SCD) in Athletes: Explanation and Clinical Context This calculator integrates multivariate risk modifiers observed in athlete populations—sex, race, sport type—and major red flags such as exertional syncope, family history, abnormal ECG, and known cardiac disease. It stratifies clinical concern but does not predict absolute probability. For athletes with hypertrophic cardiomyopathy (HCM), the va
Clinical reference for Surgical Outcome Risk Tool Sort Cardiac Module Calculator, with practical context for use alongside current guidance and professional judgment.
SVS/ISCVS Grading System for Peripheral Artery Disease: Explanation and Clinical Context The SVS/ISCVS grading system provides a standardized framework for assessing the severity of lower extremity peripheral artery disease (PAD), particularly in patients with critical limb ischemia (CLI). It incorporates key clinical parameters including rest pain, presence of ulceration, gangrene, and ankle-brachial index (ABI) val