M+QuickMedCalc
Educational reference only. Not a diagnostic tool. See full disclaimer.
All calculators
Emergency/ICUPSI

PSI (Pneumonia Severity Index)

Stratify pneumonia severity to guide disposition decisions.

Demographics

years

Comorbidities

Physical Exam

Laboratory / Imaging

PSI / PORT Score

—

About

The Pneumonia Severity Index (PSI), also known as the PORT score, stratifies community-acquired pneumonia patients into risk classes to guide disposition decisions (outpatient vs. inpatient vs. ICU). It uses 20 variables including demographics, comorbidities, physical exam findings, and laboratory results. PSI is validated for predicting 30-day mortality and helps identify low-risk patients who can be safely treated as outpatients.

Formula

PSI Score = Age (years, minus 10 if female) + Comorbidity Points + Physical Exam Points + Lab Points
Class I: Age <50, no comorbidities, normal vitals → outpatient
Class II: ≤70 | Class III: 71-90 | Class IV: 91-130 | Class V: >130

Interpretation

PSI ClassScoreMortalityDisposition
I – II≤ 700.1–0.7%Outpatient
III71 – 900.9–2.8%Observation / outpatient
IV91 – 1308.2–9.3%Inpatient
V> 13027–31%ICU consideration

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.
  2. Aujesky D, et al. Prospective comparison of three validated prediction rules for prognosis in community-acquired pneumonia. Am J Med. 2005;118(4):384-392.

FAQ

Related Calculators

CURB-65

Assess severity of community-acquired pneumonia.

APACHE II

Estimate ICU mortality risk using the APACHE II scoring system.

SOFA

Assess organ dysfunction severity using the SOFA score.

Disclaimer

Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.