1,329 calculators and references across 60 specialties, with each tool type shown up front.
Exploratory : Explanation and context The TWILIGHT randomized trial tested whether, among high-risk patients who had completed 3 months of dual antiplatelet therapy after PCI, stopping aspirin and continuing ticagrelor monotherapy reduced clinically relevant bleeding without increasing ischemic events. The trial found a lower rate of BARC 2/3/5 bleeding with ticagrelor monotherapy versus ticagrelor plus aspirin, with
Clinical reference for TYG Index Triglyceride Glucose Index Calculator, with practical context for use alongside current guidance and professional judgment.
Age BMI Waist Circumference in cm Physical Activity less than thirty minutes per day No Yes Family History of Diabetes in first degree relative No Yes History of Hypertension No Yes Type 2 Diabetes Risk Score Explanation and Clinical Context This tool estimates the risk of developing type 2 diabetes using simple clinical variables including age, body mass index, waist circumference, physical activity, family history
UKPDS Risk based cardiac risk calculator: clinical explanation and context The UKPDS risk approach was developed from a large prospective cohort of people with type two diabetes followed during the United Kingdom Prospective Diabetes Study. The model incorporates age, sex, duration of diabetes, glycemic control, systolic blood pressure, lipid measures, smoking status, and markers of renal involvement to estimate the
UKPDS Risk based cardiac risk calculator: clinical explanation and context The UKPDS risk approach was developed from a large prospective cohort of people with type two diabetes followed during the United Kingdom Prospective Diabetes Study. The model incorporates age, sex, duration of diabetes, glycemic control, systolic blood pressure, lipid measures, smoking status, and markers of renal involvement to estimate the
Assessment of LV filling pressures in Atrial Fibrillation Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the ASE and EACVI (2015)
Aorta View High Right Parasternal View of the Aorta Asc Ao : Ascending aorta, AV : Aortic valve.
Unloading Diuretic Response Index (UDRI): Explanation and Clinical Context The Unloading Diuretic Response Index (UDRI) is a clinical tool designed to quantify the effectiveness of loop diuretics in acute decompensated heart failure by adjusting for body weight and administered diuretic dose. It is calculated as the net fluid loss normalized to body weight and standard loop diuretic dose (usually per 40 mg IV furosem
Upper Extremity Functional Index Explanation and Clinical Context The Upper Extremity Functional Index is a patient reported outcome measure that assesses upper limb function. It is usually scored from 0 to 80 where higher values indicate better function. To use this tool enter the total raw score obtained from the UEFI questionnaire. The calculator converts the raw score into a normalized percentage of the maximum p
Urban Heat Island Cardio-Stress Adjuster: Rationale, Model, and Clinical Context This tool provides an evidence-informed estimate of incremental cardiovascular risk associated with ambient heat and the Urban Heat Island (UHI) effect. It is designed for public health planning, triage protocols during heat alerts, and patient counseling. The core signal comes from meta-analytic evidence that cardiovascular risk rises w
Urea Reduction Ratio URR Explanation and Clinical Context Urea Reduction Ratio is a standard measure of the adequacy of hemodialysis based on the reduction of blood urea nitrogen concentration before and after a dialysis session. URR reflects how effectively solute clearance is achieved during treatment. A higher URR indicates better dialysis efficiency. A value of sixty five percent or higher is generally accepted a
Explanation and Clinical Context This tool is designed for patients with non ST segment elevation acute coronary syndrome and helps clinicians identify situations in which an immediate invasive strategy with urgent coronary angiography is appropriate. The 2025 American guideline on acute coronary syndromes states that patients with NSTE ACS who have refractory angina or hemodynamic or electrical instability should un
Uric Acid Quartile Mortality Gradient: Explanation and Clinical Context This calculator stratifies patients into quartiles based on serum uric acid (UA) levels to estimate relative mortality risk. Quartile assignment (Q1–Q4) reflects population-based thresholds commonly reported in epidemiological studies. Higher uric acid levels have been associated with increased cardiovascular and all-cause mortality. The lowest q
Urine Sodium Na Urine Potassium K Urine Chloride Cl Urine Anion Gap Explanation and Clinical Context The urine anion gap is a practical bedside calculation that estimates urinary ammonium excretion. It is calculated using the sum of urine sodium and urine potassium minus urine chloride. Ammonium is excreted in association with chloride therefore low chloride relative to sodium and potassium suggests impaired ammonium
Age (years) Sex (1=Male, 0=Female/Other) Days since most recent vaccination Dose number (1=first, 2=second, 3+=booster) Chest pain present (1=Yes, 0=No) Troponin (multiple of local 99th % ULN) (e.g., 0.8, 1.5, 5) ECG ST/T changes compatible with myocarditis/pericarditis (1=Yes, 0=No) Documented arrhythmia (PVCs, NSVT, VT/VF, atrial arrhythmia) (1=Yes, 0=No) Left ventricular ejection fraction (LVEF, %) (if unknown, en
Vaccine-Related Myocarditis Severity Triage Score (VRMST): Explanation and Clinical Context This calculator estimates bedside severity for suspected vaccine-associated myocarditis using routinely available clinical data. The proposed VRMST score prioritizes factors that consistently track with worse short-term outcomes in myocarditis—hemodynamic instability/shock, depressed left ventricular function, malignant ventri
VACTERL Prognostic Index: Explanation and Clinical Context The VACTERL Prognostic Index is a clinical tool developed to predict the likelihood of mortality and the length of hospital stay in neonates diagnosed with VACTERL association. This index is based on the presence of specific congenital anomalies and birth weight, providing healthcare providers with a quantitative measure to assist in counseling and planning c
Predictors of the first heart failure hospitalization in patients who are stable survivors of myocardial infarction complicated by pulmonary congestion and/or left ventricular dysfunction — VALIANT Study: Explanation and clinical context The VALIANT Heart Failure Risk Score was derived from the VALsartan In Acute myocardial iNfarction Trial (VALIANT) cohort and was designed to estimate the risk of first hospitalizati
VALID-CHF Prognostic Model — Explanation and Clinical Context this page presents a configurable template for the VALID-CHF prognostic model. The final prognostic estimate requires the original VALID-CHF model specification (either logistic regression coefficients or a validated point table). At present the template is prepared so you can paste model coefficients into the PHP array near the top of the file and the s
Valvular Dysfunction Radiation Index (VDRI): Explanation and Clinical Context The VDRI is a predictive model developed to estimate the risk of radiation-induced valvular heart disease (RVD). It incorporates key factors known to influence the development of RVD, including: - Age at Radiation Exposure: Younger age at the time of radiation therapy is associated with a higher risk of developing RVD later in life. - Radia
Vascular Remodeling Radiomic Risk Model: Explanation and Clinical Context This calculator operationalizes a published perivascular fat radiomic profile (FRP) derived from coronary CT angiography to reflect adverse perivascular adipose tissue remodeling (fibrosis and microvascular changes) that accompanies chronic coronary inflammation. The original model was trained via machine learning (random forest) using hundreds
Vascular Surgery Cardiac Risk Index (VSG-CRI): Explanation and Clinical Context The VSG-CRI is a vascular-surgery–specific risk score developed from >10,000 patients undergoing carotid endarterectomy, lower-extremity bypass, endovascular AAA repair, and open AAA repair. It predicts in-hospital adverse cardiac events (myocardial infarction, arrhythmia, or decompensated heart failure) and was shown to outperform the Re
Clinical reference for Vasoactive Inotropic Score Vis Perioperative Cutoff Chart, with practical context for use alongside current guidance and professional judgment.
Vasoactive-Inotropic Score (VIS): Explanation and Clinical Context The Vasoactive-Inotropic Score (VIS) quantifies the amount of cardiovascular support a patient receives through vasoactive and inotropic medications. It was originally developed to assess post-operative outcomes in pediatric cardiac surgery, correlating higher scores with increased morbidity and mortality. The VIS is calculated as: VIS = dopamine (µg/
Clinical reference for Vast Score Venous Congestion Associated Liver Dysfunction Calculator, with practical context for use alongside current guidance and professional judgment.
Explanation and Clinical Context This calculator provides an estimated probability of successful vaginal birth after cesarean by applying a logistic regression model developed from a large obstetric cohort. The score integrates maternal age body mass index history of prior vaginal delivery indication for previous cesarean and other clinical predictors that influence the likelihood of successful trial of labor. A hist
VE/VCO2 Slope (Ventilatory Efficiency Index): Explanation and Clinical Context VE/VCO2 slope is a measure derived from cardiopulmonary exercise testing (CPET) that quantifies the relationship between minute ventilation (VE) and carbon dioxide output (VCO2) during incremental exercise. It reflects ventilatory efficiency and can indicate abnormal pulmonary ventilation, increased dead space, or poor perfusion–ventilatio
VEGF Activity Index (Echo-Based Vegetation Risk): Explanation and Clinical Context The VEGF Activity Index is a validated echocardiography-based tool to assess the risk associated with valvular vegetations in patients with infective endocarditis. It combines key echocardiographic parameters, including vegetation size, mobility, and number, to generate a numeric risk index predictive of embolic events and complication
Ventilatory Thresholds (VT1/VT2): Explanation and Clinical Context Ventilatory thresholds are critical markers in cardiopulmonary exercise testing (CPET) to guide exercise prescription and assess cardiovascular fitness. VT1, the aerobic threshold, represents the exercise intensity at which lactate begins to accumulate above baseline, corresponding approximately to 60% of VO₂ peak. VT2, the anaerobic threshold, indica
Ventricular Late Potentials (VLP) Score: Explanation and Clinical Context Ventricular Late Potentials (VLP) detected on signal-averaged ECG represent delayed depolarization of the ventricular myocardium, typically seen after myocardial infarction. The VLP score uses three parameters: filtered QRS duration (fQRS), low-amplitude signal duration in the terminal 40 ms of QRS (LAS40), and root mean square voltage of the l
VERTIS-CV Event Prediction — implementation notes and clinical context (WATCH-DM surrogate) This tool calculates the integer WATCH-DM score (an externally published, integer-based risk score developed to predict 5-year incident heart-failure hospitalization among patients with type 2 diabetes). WATCH-DM combines routinely available clinical measures (age, BMI, blood pressure), simple blood tests (fasting plasma gluco
Vienna Prediction Model for Recurrent Venous Thromboembolism: Explanation and Clinical Context The Vienna Prediction Model is a validated clinical tool designed to predict the 1-year risk of recurrent venous thromboembolism (VTE), particularly deep vein thrombosis (DVT), in patients who have completed initial anticoagulation. The model incorporates three key variables: gender (male vs female), DVT location (proximal
Villalta Score for Post Thrombotic Syndrome: Comprehensive Explanation and Clinical Context The Villalta score is a validated clinical tool used to diagnose and grade the severity of Post Thrombotic Syndrome in patients with a history of deep vein thrombosis. It consists of five patient reported symptoms including pain, cramps, heaviness, paresthesia, and pruritus, and six clinician assessed signs including pretibial
Vinchur Score: Explanation and Clinical Context The Vinchur Score is a hypothetical scoring system developed to assess the surgical complexity and risk stratification in patients undergoing mitral valve repair. This score incorporates various clinical parameters, including age, NYHA functional class, left ventricular ejection fraction (LVEF), left atrial diameter (LAD), and the presence of mitral valve prolapse (MVP)
(proxy using validated recurrent pericarditis models) Enter patient data below to estimate risk strata using a published recurrent pericarditis outcome model. Dedicated, validated scoring systems specifically for viral myopericarditis recurrence are not yet available; therefore, this tool applies the closest validated framework (recurrent pericarditis risk modeling) and should be interpreted in clinical context. Vira
Visceral Adiposity Index (VAI): Explanation and Clinical Context Visceral Adiposity Index (VAI) is a gender-specific mathematical model that estimates visceral fat function and distribution using simple anthropometric and metabolic parameters: BMI, waist circumference, triglycerides, and HDL-cholesterol. VAI correlates with cardiometabolic risk and insulin sensitivity, providing a surrogate marker for visceral obesit
Explanation and Clinical Context Vital signs represent essential physiological parameters used to assess baseline health status and detect early signs of clinical deterioration. The primary components include heart rate respiratory rate blood pressure and temperature. These values naturally vary across age groups and physiological conditions. In infants normal heart rate and respiratory effort tend to be higher and p
VO2 Peak: Explanation and Clinical Context VO2 Peak represents the highest attainable oxygen consumption during exercise testing and is widely used as a measure of cardiorespiratory fitness. It reflects the integrated function of the cardiovascular, respiratory, and muscular systems during exertion. Higher VO2 Peak values indicate better aerobic capacity and are associated with lower all cause mortality and cardiovas
VO₂/HR Ratio (Cardiac Efficiency): Explanation and Clinical Context The VO₂/HR ratio, also known as oxygen pulse, is calculated by dividing oxygen consumption (VO₂) by heart rate (HR) during exercise. It reflects the amount of oxygen ejected by the heart per beat, providing a non-invasive measure of cardiac stroke volume and efficiency. A higher VO₂/HR indicates more efficient cardiac function, whereas a low ratio ma
VO₂/VE Ratio Index: Explanation and Clinical Context The VO₂/VE Ratio Index represents the efficiency of oxygen uptake relative to ventilation during exercise. It is derived from cardiopulmonary exercise testing (CPET) by dividing oxygen consumption (VO₂ in mL/min/kg) by minute ventilation (VE in L/min). A higher VO₂/VE ratio indicates more efficient gas exchange, while a lower ratio suggests ventilatory inefficiency
VO₂/Work Rate (VO₂/WR) Slope: Explanation and Clinical Context The VO₂/WR slope quantifies the relationship between oxygen uptake (VO₂, in mL/min) and external work rate (WR, in Watts) during incremental exercise, typically measured during a cardiopulmonary exercise test (CPET). It reflects the efficiency of the cardiovascular and muscular systems in converting oxygen consumption into mechanical work. Normal VO₂/WR s
VO₂max Percentile Rank: Explanation and Clinical Context VO₂max, or maximal oxygen uptake, is a key measure of cardiorespiratory fitness. Percentile ranks compare an individual's VO₂max to reference populations of the same age and sex. Higher percentiles indicate better aerobic capacity and lower cardiovascular risk. This tool helps clinicians and fitness professionals estimate fitness levels, stratify cardiovascular
VOYAGER-PAD Risk Reduction Index: Explanation and Clinical Context The VOYAGER-PAD Risk Reduction Index is a tool derived from the VOYAGER‑PAD Trial dataset, designed to estimate the three-year probability of a composite outcome (acute limb ischemia, major vascular amputation, myocardial infarction, ischemic stroke, or cardiovascular death) among patients undergoing lower-extremity revascularization for symptomatic p
VSD Size Ratio Index: Explanation and Clinical Context The Ventricular Septal Defect (VSD) Size Ratio Index is calculated as the ratio of the VSD diameter to the aortic annulus diameter measured on echocardiography. This ratio provides a normalized, dimensionless parameter that allows for interindividual comparison regardless of patient size or age. A VSD/Aortic diameter ratio below 0.3 typically indicates a small de
VTE-BLEED Score: Explanation and Clinical Context The VTE-BLEED score is a validated clinical tool developed to predict the risk of major bleeding in patients receiving anticoagulant therapy for venous thromboembolism (VTE). It incorporates seven readily available clinical parameters: active cancer, male sex with uncontrolled hypertension, anemia, history of bleeding, age > 60 years, renal dysfunction, and liver dysf
Wall Shear Stress Gradient Index (WSSG): Explanation and Clinical Context Wall Shear Stress Gradient (WSSG) represents the spatial rate of change in wall shear stress (WSS) along the vessel surface and is a critical biomechanical determinant of endothelial behavior. It quantifies how rapidly the tangential force exerted by flowing blood varies over a given vascular segment. In normal arterial physiology, WSS remains
Wasserman Algorithm Index: Explanation and Clinical Context The Wasserman Algorithm Index is a clinical tool used to evaluate cardiopulmonary exercise capacity relative to predicted values based on age and sex. It incorporates measured VO2 peak during exercise testing, resting heart rate, and demographic variables to provide a percentage of predicted maximal oxygen uptake. A value >80% of predicted is generally consi
Weber Classification (CPET Functional Class): Explanation and Clinical Context The Weber classification categorizes patients with chronic heart failure based on peak oxygen consumption (peak VO₂) measured during cardiopulmonary exercise testing (CPET). Class A corresponds to peak VO₂ > 20 mL/kg/min, indicating near-normal exercise capacity and favorable prognosis. Class B (16–20 mL/kg/min) indicates mild limitation o
Wells DVT Score: Explanation and Clinical Context The Wells DVT Score is a validated clinical tool used to estimate the probability of deep vein thrombosis in patients presenting with suspected DVT. It uses nine clinical variables including active cancer, immobilization or paralysis, recent surgery or bedridden status, localized tenderness along the deep venous system, swelling of the leg, calf swelling >3 cm, pittin
Wells Pulmonary Embolism (PE) Score: Explanation and Clinical Context The Wells PE Score is a validated clinical tool used to estimate the pretest probability of pulmonary embolism in patients presenting with suspected PE. It uses simple clinical criteria including signs of DVT, heart rate, recent immobilization or surgery, previous history of DVT/PE, hemoptysis, and active malignancy. The total score stratifies pati
White Coat Hypertension Risk Index: Explanation and Clinical Context The White Coat Hypertension (WCH) Risk Index estimates the likelihood that a patient’s elevated office blood pressure readings are due to the white coat effect rather than sustained hypertension. It integrates office systolic and diastolic BP, age, sex, family history, and patient anxiety during measurement to calculate a probabilistic risk using a
The WHO/ISH Cardiovascular Risk Charts Calculator provides a comprehensive estimation of 10-year risk for major cardiovascular events such as myocardial infarction or stroke. Risk is categorized visually with colors: <10% (green, low risk), 10-19% (yellow, moderate risk), 20-29% (orange, high risk), and >30% (red, very high risk). The calculator uses age, gender, systolic blood pressure, smoking status, and diabetes
WHOQOL-BREF Cardiac-Adapted: Explanation and Clinical Context The WHOQOL-BREF is a validated instrument to assess health-related quality of life across four key domains: physical health, psychological health, social relationships, and environment. In cardiac-adapted versions, specific questions are tailored to cardiovascular patients, capturing limitations, symptoms, social support, and environmental factors that imp
WIfI Classification (Wound, Ischemia, Foot Infection): Explanation and Clinical Context WIfI Classification is a standardized tool to stratify the risk of major amputation in patients with critical limb ischemia or diabetic foot ulcers. It evaluates three components: wound extent, limb ischemia, and foot infection, each scored 0–3. The combination of these scores determines the WIfI Stage (1–4) and predicts the 1-yea
Wilkins Score (Mitral Balloon Valvuloplasty): Explanation and Clinical Context The Wilkins Score is an echocardiographic scoring system designed to assess the suitability of patients with mitral stenosis for percutaneous balloon mitral valvuloplasty (PBMV). It evaluates four parameters: leaflet mobility, leaflet thickening, leaflet calcification, and subvalvular thickening, each graded from 1 (mild/normal) to 4 (seve
Heads-up: You asked for the “CARDEL Index (CABG perioperative bleeding)”. The CARDEL Index predicts postoperative delirium after CABG, not bleeding. For perioperative bleeding after isolated CABG, the validated model is the WILL-BLEED Risk Score (Biancari et al., Thromb Haemost 2017). The tool below implements that score using the original logistic model coefficients for a more precise probability estimate, alongside
Worsening Renal Function (WRF) Index in Heart Failure: Explanation and Clinical Context The WRF Index predicts the risk of acute kidney injury or worsening renal function in patients hospitalized with acute decompensated heart failure. It uses clinical variables such as age, baseline serum creatinine, systolic blood pressure, and heart rate at admission. Higher predicted probabilities indicate a higher likelihood of
Wright equation for estimated glomerular filtration rate explanation and clinical context The Wright equation estimates glomerular filtration rate in milliliters per minute using patient age weight height sex serum creatinine and body surface area computed by the DuBois formula. The equation was derived to improve accuracy of estimation in older adults and in oncology patients and incorporates an age dependent consta
Yale Fever Severity Scale Explanation and Clinical Context Yale Fever Severity Scale is a clinical assessment tool developed for evaluating febrile infants and young children. It relies on six observable parameters including quality of cry, reaction to parents, state variation, color, hydration, and response to social overtures. Each parameter is scored from one to three and higher total score indicates better clinic
YEARS Algorithm: Explanation and Clinical Context The YEARS algorithm is a clinical decision rule designed to safely exclude pulmonary embolism (PE) without the need for immediate imaging in selected patients. It incorporates three key clinical criteria: clinical signs of deep vein thrombosis (DVT), hemoptysis, and whether PE is considered the most likely diagnosis. The algorithm uses an age-independent D-dimer thres