Clinical Calculators

Identifies elevated AG metabolic acidosis. Corrected for albumin.

Fractional excretion to differentiate pre-renal from ATN.

Adjusts serum sodium for hyperglycemia-induced osmotic shift.

Creatinine clearance for drug dosing. Uses ideal or actual body weight.

Adjusts calcium for low albumin. Use ionized Ca when available.

Expected PCO₂ in metabolic acidosis. Detects concurrent respiratory disorder.

Stroke risk in atrial fibrillation. Guides anticoagulation decisions.

AHA PREVENT (Predicting Risk of cardiovascular disease EVENTs) equations, Khan et al. Circulation 2024. Adopted by 2026 ACC/AHA Dyslipidemia Guideline -replaces the 2013 Pooled Cohort Equation. Validated ages 30-79, no race input, sex-specific, includes CKD (eGFR), antihypertensive and statin use. Risk categories: low <3% / borderline 3-<5% / intermediate 5-<10% / high ≥10%. Drives 2026 statin and LDL-target decisions in primary prevention. Also returns the 30-year ASCVD risk (ages 30-59), which decides treatment when 10-year risk is low, and interprets the result with the guideline's CPR steps (Calculate, Personalize with risk enhancers, Reclassify with CAC), including the diabetes and CKD indications that apply regardless of the score. Optional CAC score: enter a calcium score and the result is reclassified to the guideline's CAC-specific plan and LDL-C goal (0, 1-99, 100-299, 300-999, ≥ 1000), including when a zero may and may not be used to defer a statin.

Legacy 2013 Pooled Cohort Equation (ACC/AHA 2013/2018). Retired by the 2026 ACC/AHA Dyslipidemia Guideline -use the PREVENT calculator above for current 2026 guidance. PCE retained here for cross-reference and patients still being managed on prior thresholds. Validated for ages 40-79 without prior CV event, stroke, or PAD. Inputs: age, sex, race, total cholesterol, HDL, SBP, treated HTN status, DM, smoking. Tends to overestimate risk vs PREVENT, especially in Black patients and the elderly.

Pretest probability of pulmonary embolism.

Use ONLY if pre-test probability is already LOW (gestalt < 15%). All 8 criteria must be negative to rule out PE without a D-dimer.

30-day mortality risk in acute PE. Identifies outpatient-eligible patients (score 0) vs those needing admission (score ≥ 1).

11 exclusion criteria for home treatment of acute PE. Any single YES = not an outpatient candidate.

Estimates average arterial pressure during one cardiac cycle

Bazett formula -corrects QT interval for heart rate

Severity scoring for community-acquired pneumonia. Guides disposition.

Alveolar–arterial oxygen gradient -evaluates oxygenation defect

Modified Medical Research Council Dyspnea Scale. Quantifies functional impairment from breathlessness. Drives the symptom axis of COPD ABE classification (mMRC ≥ 2 = high symptoms → Group B or E).

8-item symptom questionnaire. Each item scored 0-5; total 0-40. CAT ≥ 10 = high symptom burden (Group B or E in COPD ABE classification). Used alongside mMRC.

Pre-test probability of obstructive sleep apnea. 8 yes/no items, 1 point each. Validated for pre-op screening and high-yield in resistant HTN (OSA is the #1 secondary cause). Score ≥ 3 = at risk for OSA; ≥ 5 = high probability of MODERATE-TO-SEVERE OSA.

Quantify consciousness. Range 3–15. GCS ≤ 8 = intubate for airway protection.

National Early Warning Score -SSC 2026 recommended sepsis screening tool. Scores 7 parameters.

Modified Early Warning Score -simpler alternative to NEWS. Score ≥5 = urgent clinical review.

11-item stroke severity scale. Drives thrombectomy eligibility (≥ 6), antiplatelet choice (≤ 3 → DAPT per CHANCE/POINT), and prognosis. Score before tPA, after tPA, and daily.

Convert between opioids using total daily OME. Always reduce calculated equivalent by 25–50% for incomplete cross-tolerance when rotating. Methadone is NOT linear, consult palliative care.

Model for End-Stage Liver Disease. Transplant priority and 3-month mortality.

Weight-based classification for nutritional status

Glucocorticoid equivalence -converts between common steroids