PSI / PORT Score
Pneumonia Severity Index for community-acquired pneumonia risk stratification.
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Why use it
Validated in >50,000 patients; identifies low-risk patients suitable for outpatient treatment, reducing unnecessary hospitalization.
About
The Pneumonia Severity Index (PSI), also known as the PORT Score, stratifies adults with community-acquired pneumonia (CAP) into five risk classes to guide site-of-care decisions (outpatient vs. inpatient vs. ICU).
When to use
- Adults (≥18 years) presenting with community-acquired pneumonia
- Determining need for hospitalization vs. outpatient management
- Complementary to CURB-65 for risk stratification
Formula
Demographic: Age (years) for men; Age-10 for women; +10 if NH resident
Comorbidity: +30 neoplasm; +20 liver disease; +10 CHF; +10 cerebrovascular; +10 renal disease
Exam: +20 altered mental status; +20 RR≥30; +20 SBP<90; +15 temp<35 or ≥40°C; +10 HR≥125
Labs: +30 pH<7.35; +20 BUN≥30mg/dL (11mmol/L); +10 Na<130; +10 glucose≥250mg/dL (14mmol/L); +10 Hct<30%; +10 PaO2<60mmHg or SaO2<90%; +10 pleural effusion
Pearls & pitfalls
- Class I patients are <50y, no comorbidities, normal mental status, and normal vital signs — no point calculation needed.
- PSI is more complex than CURB-65 but better validated for low-risk identification.
- Does not replace clinical judgment; consider social factors for site-of-care decisions.
Next steps
Class I-II: outpatient treatment. Class III: short hospitalization or observation. Class IV-V: inpatient; Class V consider ICU.
Evidence
Fine et al. NEJM 1997. Validated in 38,039 patients across 3 cohorts. AUC 0.82-0.89 for 30-day mortality.