PSI / PORT Score

What This Calculator Measures

Predicts 30-day mortality in community-acquired pneumonia to guide site-of-care decisions, from outpatient to ICU admission.

How to Use

1. Enter demographics, comorbidities, and vital signs.
2. Enter available laboratory results; arterial pH and PaO2 may be left blank.
3. The score and PSI class (I–V) are computed automatically.
4. Use the class to inform site-of-care decisions.

How the Calculation Works

The Pneumonia Severity Index starts with points equal to age (minus 10 for women), then adds weighted points for comorbidity/risk items (nursing-home 10, neoplastic disease 30, liver disease 20, CHF 10, cerebrovascular 10, renal disease 10, altered mental status 20, pleural effusion 10), vital-sign abnormalities (respiratory rate >= 30: 20, systolic BP < 90: 20, temperature < 35 or >= 40 C: 15, heart rate >= 125: 10), and laboratory abnormalities (pH < 7.35: 30, BUN >= 30: 20, sodium < 130: 20, glucose >= 250: 10, hematocrit < 30: 10, PaO2 < 60: 10). The total assigns a PORT risk class I-V.

Variables Explained

Interpretation Guide

Class I–II (≤70 points): low mortality (~0.1–0.6%), consider outpatient. Class III (71–90): low-intermediate risk, consider observation or inpatient. Class IV (91–130): moderate risk (~8–9%), admit. Class V (>130): high risk (~27–31%), admit and consider ICU.

Clinical Significance

The PSI/PORT score is a landmark, extensively validated prediction tool that has shaped site-of-care decisions for community-acquired pneumonia for over two decades.

When It Is Useful

• Risk stratification of community-acquired pneumonia in adults
• Supporting discharge-versus-admission decisions
• Identifying patients who may need ICU-level care

When It Is Not Useful

• Hospital-acquired or ventilator-associated pneumonia
• Immunocompromised patients outside the original validation populations
• Pregnant women, in whom the original cohort was not validated

Common Mistakes

• Forgetting to subtract 10 points for female sex, which inflates the total and can push the patient into a higher risk class.
• Assigning class I to a patient with any comorbidity, when class I requires age under 50, no comorbidities, and no risk findings.
• Entering the BUN in mmol/L instead of the mg/dL units the score expects, which miscalculates the laboratory points.

Limitations

• Requires several laboratory values, making it less practical than CRB-65 at the bedside.
• Class I designation requires absence of all comorbidities and risk findings.
• The rule was derived in adults with CAP and may not generalize to all populations.
• The score supports but does not dictate site-of-care decisions — social factors, oxygen requirements, and other acute considerations can justify a different disposition.

Worked Example

A 68-year-old nursing home man with heart failure is confused. RR 24/min, BP 100/70 mmHg, temperature 38.2 °C, HR 98 bpm, pH 7.36, BUN 35 mg/dL, sodium 131 mmol/L, glucose 150 mg/dL, hematocrit 31%, PaO2 70 mmHg, no pleural effusion.

Expected Result: PSI class IV (score 128) — moderate mortality risk (~8–9%). Admit to hospital.

Evidence & References

Source:

Emergency Medicine / Pulmonology

Reference:

Fine MJ, et al. N Engl J Med. 1997;336(4):243-250.

Content updated:

2026-08

1. Fine MJ, et al. JAMA. 1996;275(2):134-141.

References

1. Fine MJ, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med. 1997;336(4):243-250. (Original Derivation)
2. Fine MJ, et al. Prognosis and outcomes of patients with community-acquired pneumonia: a meta-analysis. JAMA. 1996;275(2):134-141. (Meta-Analysis)

Frequently Asked Questions