ER Calculators

⚠️ Clinical Disclaimer: Calculators are decision-support tools only. Always apply clinical judgment. Scores do not replace physician assessment.

🔍 PERC Rule — Rule OUT PE (use first)

All 8 must be absent to PERC-negative. Use only if Wells PE <2 (low pre-test probability).

Age ≥ 50

HR ≥ 100 bpm

SpO₂ < 95% on room air

Unilateral leg swelling

Hemoptysis

Recent surgery or trauma (≤4 weeks)

Prior PE or DVT

Hormone use (OCP, HRT, or estrogenic)

Check criteria above

All 8 must be absent to rule out PE without further testing.

⚖️ Wells PE Score

Clinical signs/symptoms of DVT+3

PE is #1 diagnosis OR equally likely+3

HR > 100 bpm+1.5

Immobilization ≥3 days OR surgery in past 4 weeks+1.5

Prior PE or DVT+1.5

Hemoptysis+1

Malignancy (treatment within 6 months or palliative)+1

Select criteria above

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❤️ HEART Score — Chest Pain Risk Stratification

Each category scored 0–2. Score ≤3 = low risk (MACE <2%). Use with serial troponins.

H — History

Slightly suspicious — mostly non-specific features0

Moderately suspicious — features of ACS but not classic+1

Highly suspicious — classic exertional, pressure-type, radiation+2

E — EKG

Normal0

Non-specific repolarization disturbance (LBBB, pacemaker, early repol, LVH, ST depression ≤1mm)+1

Significant ST deviation — ST depression >1mm, new ST elevation, T-wave inversion+2

A — Age

Age < 450

Age 45–64+1

Age ≥ 65+2

R — Risk Factors (HTN, hypercholesterolemia, DM, obesity BMI>30, smoking, family hx, atherosclerosis)

No known risk factors0

1–2 risk factors+1

≥3 risk factors OR known CAD / atherosclerotic disease+2

T — Troponin (relative to institutional upper limit of normal)

≤ normal limit (≤1× ULN)0

1–3× ULN+1

>3× ULN+2

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Select all categories above

Score each domain to calculate HEART score.

📊 HEART Score Interpretation

6-week MACE risk (death, MI, revascularization):

0–3 — Low Risk
MACE ~1.7%. Eligible for early discharge with outpatient follow-up if serial troponins negative. Shared decision-making discussion documented.

4–6 — Moderate Risk
MACE ~12–17%. Consider observation, stress testing, or cardiology consult. Not safe for routine discharge without further evaluation.

7–10 — High Risk
MACE ~50–65%. Early invasive strategy indicated. Cardiology consult, admission, likely catheterization.

⚠️ HEART score does not replace clinical judgment. Patients with STEMI, new LBBB, or hemodynamic instability require immediate intervention regardless of score.

🫁 YEARS Algorithm — PE CT reduction strategy

Select YEARS criteria and enter D-dimer (ng/mL FEU).

Clinical signs of DVT

Hemoptysis

PE most likely diagnosis

D-dimer (ng/mL FEU)

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Select criteria + D-dimer

0 criteria: D-dimer <1000 rules out PE. ≥1 criterion: D-dimer <500 rules out PE.

📊 YEARS Interpretation

0 YEARS criteria
Use D-dimer cutoff of <1000 ng/mL FEU to rule out PE.

1 or more YEARS criteria
Use D-dimer cutoff of <500 ng/mL FEU to rule out PE.

Use in low/intermediate pre-test probability patients with clinical judgment and local protocol alignment.

🧠 ABCD2 Score — TIA early stroke risk

Age ≥60 years+1

Initial BP ≥140 systolic or ≥90 diastolic+1

Clinical features

Unilateral weakness+2

Speech disturbance without weakness+1

Other symptoms0

Duration

≥60 minutes+2

10–59 minutes+1

<10 minutes0

Diabetes+1

—

Complete clinical feature + duration

ABCD2 helps estimate early stroke risk after suspected TIA.

📊 ABCD2 Interpretation

0–3 Low risk
Often outpatient pathway if evaluation is otherwise reassuring and follow-up is rapid.

4–5 Moderate risk
Consider admission vs expedited stroke/TIA clinic based on resources and exam/imaging.

6–7 High risk
High early stroke risk; admission/urgent stroke pathway strongly favored.

🧠 NIH Stroke Scale — 15 items, 0–42

Score each item by observed performance. Do not change scores after coaching the patient. UN (untestable) is allowed for motor items only and counts as 0.

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Score all 15 items

NIHSS guides stroke severity, treatment eligibility, and outcomes.

📊 NIHSS Severity

0 — No stroke symptoms

1–4 — Minor stroke

5–15 — Moderate stroke

16–20 — Moderate–severe stroke

21–42 — Severe stroke

Use NIHSS in conjunction with last-known-well time, imaging, and contraindication review when assessing IV thrombolysis or thrombectomy eligibility. Document baseline and serial scores.

❤️ CHA2DS2-VASc — AF stroke risk

Sex

Male0

Female+1

Age

≥75 years+2

65–74 years+1

<65 years0

Congestive heart failure/LV dysfunction+1

Hypertension+1

Diabetes mellitus+1

Prior stroke/TIA/thromboembolism+2

Vascular disease (MI/PAD/aortic plaque)+1

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Select sex + age + risk factors

Use with AF documentation and shared decision-making around anticoagulation.

📊 CHA2DS2-VASc Thresholds

Lower risk
Men 0 / Women 1: anticoagulation usually not indicated.

Intermediate
Men 1 / Women 2: consider anticoagulation based on bleeding risk and shared decision-making.

Higher risk
Men ≥2 / Women ≥3: anticoagulation generally recommended unless contraindicated.

🦵 Wells DVT Score

Active cancer (treatment ongoing, within 6 months, or palliative)+1

Paralysis, paresis, or recent plaster immobilization of lower extremity+1

Bedridden >3 days OR major surgery within 12 weeks requiring GA/regional anesthesia+1

Localized tenderness along deep venous system+1

Entire leg swollen+1

Calf swelling >3cm vs asymptomatic leg (10cm below tibial tuberosity)+1

Pitting edema confined to symptomatic leg+1

Collateral superficial veins (non-varicose)+1

Alternative diagnosis at least as likely as DVT−2

Select criteria above

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📊 Interpretation

Wells DVT Score interpretation:

≤1 — Low probability
DVT prevalence ~5%. D-dimer negative → DVT excluded. D-dimer positive → ultrasound.

2–6 — Moderate probability
DVT prevalence ~17%. Compression ultrasound. If negative + D-dimer negative → DVT excluded.

≥7 — High probability
DVT prevalence ~53%. Compression ultrasound regardless of D-dimer. If negative, repeat in 1 week or MRI.

✅ Eligibility Check

Patient MUST meet ALL of the following to apply the rule:

GCS score of 13–15

Witnessed loss of consciousness, amnesia, or confusion

Age ≥ 16 years

Injury within last 24 hours

No coagulopathy / not on anticoagulants

Check eligibility above

🔴 High-Risk Factors — CT if ANY present

Predicts need for neurological intervention:

GCS < 15 at 2 hours post-injury

Suspected open or depressed skull fracture

Any sign of basal skull fracture (hemotympanum, raccoon eyes, CSF leak, Battle's sign)

Vomiting ≥ 2 episodes

Age ≥ 65

Check factors above

🟡 Medium-Risk Factors — CT if ANY present

Predicts brain injury on CT:

Amnesia before impact ≥ 30 minutes

Dangerous mechanism (pedestrian struck by MVC, ejected, fall >3 feet or 5 stairs)

Check factors above

📋 Overall Recommendation

Complete eligibility + factors above

Canadian CT Head Rule applies to minor head injury (GCS 13–15) with LOC, amnesia, or confusion.

🩸 LRINEC (Necrotizing Soft Tissue Infection)

LRINEC is a risk stratification/documentation tool — limited sensitivity (do NOT use to rule out nec fasc).

CRP (mg/L)

WBC (×10³/µL)

Hgb (g/dL)

Na (mmol/L)

Creatinine (mg/dL)

Glucose (mg/dL)

—

Enter labs above

LRINEC: ≤5 low, 6–7 intermediate, ≥8 high (risk stratification only).

⚠️ Fournier’s Gangrene Severity Index (FGSI)

Prognostic score (mortality risk / ICU justification). Commonly cited: FGSI > 9 → high mortality risk.

Temp (°C)

Na (mmol/L)

K (mmol/L)

Creatinine (mg/dL)

Hct (%)

WBC (×10³/µL)

HCO₃ (mmol/L, venous)

—

Enter vitals/labs above

FGSI is prognostic. A commonly used threshold is >9 (high mortality risk).

🌡️ SIRS

Temp >38°C or <36°C

HR >90

RR >20 or PaCO₂ <32

WBC >12 or <4 or bands >10%

Select criteria above

≥2 suggests systemic inflammatory response.

🧠 qSOFA

RR ≥22

SBP ≤100

Altered mentation

Select criteria above

≥2 associated with higher mortality risk → escalate care.

💥 Shock Index

SBP

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Enter HR + SBP

Shock Index = HR/SBP. >0.9 is concerning for occult shock in many contexts.

🦠 Centor / McIsaac (Strep Pharyngitis)

Centor criteria (+1 each): tonsillar exudate, tender anterior cervical nodes, fever, absence of cough. McIsaac adds age adjustment.

Tonsillar exudates+1

Tender anterior cervical adenopathy+1

Fever (subjective or ≥38°C)+1

Absence of cough+1

Age adjustment (McIsaac)

Age 3–14+1

Age 15–440

Age ≥45−1

Select criteria above

Recommendation will appear here.

👶 PECARN Pediatric Head Injury

Decision support for minor blunt head trauma (GCS 14–15). Choose age group, then select findings.

Age group

< 2 years

≥ 2 years

—

Select age group + findings

Recommendation will appear here.

PECARN supports CT vs observation; always use clinical judgment, and consider non-accidental trauma.

🌡️ Peds Fever (0–60d)

Full workflow is on the dedicated page (labs, age bands, disposition suggestions).

Open Peds Fever Page

Quick note

Use the 0–60 day fever algorithm on the Peds Fever page for age-based evaluation and disposition.