Calculate the PSI/PORT score to assess pneumonia severity, predict 30-day mortality, and guide inpatient vs. outpatient treatment decisions.
The Pneumonia Severity Index (PSI), also known as the PORT score, is a validated clinical prediction tool that stratifies patients with community-acquired pneumonia (CAP) into five risk classes based on 30-day mortality. Developed by Fine et al. in 1997 and validated in over 50,000 patients, it remains one of the most widely used tools for pneumonia disposition decisions.
The PSI assigns points based on demographics (age, sex), comorbidities (cancer, liver disease, heart failure, cerebrovascular disease, renal disease), physical examination findings (altered mental status, tachypnea, hypotension, temperature extremes, tachycardia), and laboratory/imaging results (pH, BUN, sodium, glucose, hematocrit, PaO2, pleural effusion).
Patients in Risk Classes I and II (low risk, mortality < 1%) can generally be treated as outpatients. Class III patients (moderate risk) may benefit from brief observation. Classes IV and V (high risk, mortality 8–31%) typically require inpatient treatment, with Class V patients potentially needing ICU-level care. Check the example with realistic values before reporting.
The PSI/PORT score is recommended by the American Thoracic Society and Infectious Disease Society of America for triage of community-acquired pneumonia. Studies consistently show that 30–50% of CAP patients who are hospitalized could be safely treated as outpatients based on PSI scoring, reducing healthcare costs while maintaining patient outcomes. This calculator helps clinicians apply the validated algorithm quickly and accurately at the bedside.
PSI Score = Age (years, −10 if female) + Nursing home (+10) + Comorbidities (Neoplasm +30, Liver +20, CHF/CVD/Renal +10 each) + Exam (Altered MS +20, RR≥30 +20, SBP<90 +20, Temp <35/≥40 +15, HR≥125 +10) + Labs (pH<7.35 +30, BUN≥30 +20, Na<130 +20, Glucose≥250 +10, Hct<30 +10, PaO₂<60 +10, Effusion +10)
Result: PSI Score: 65, Risk Class II, 30-day mortality 0.6%, outpatient treatment recommended
A 65-year-old male with no comorbidities or abnormal findings scores 65 points (age alone). This places him in Risk Class II (score ≤ 70) with a predicted 30-day mortality of 0.6%, supporting outpatient management.
Use consistent units, verify assumptions, and document conversion standards for repeatable outcomes.
Most mistakes come from mixed standards, rounding too early, or misread labels. Recheck final values before use. ## Practical Notes
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Use this note as a quick practical validation checkpoint. ## Practical Notes
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Use as a sanity check against edge-case outputs. ## Practical Notes
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Document expected ranges when sharing results.
PSI is more comprehensive (20 variables) and better at identifying low-risk patients for outpatient treatment. CURB-65 is simpler (5 variables) and better at identifying high-risk patients. Both are guideline-recommended. PSI may underestimate risk in young patients with severe disease but no comorbidities.
No. The PSI was developed and validated specifically for community-acquired pneumonia. Hospital-acquired and ventilator-associated pneumonia have different risk factors and require different severity assessment tools.
No. PSI should supplement, not replace, clinical judgment. Social factors (homelessness, inability to take oral medications), hypoxia not captured by PaO2, and clinical instability may warrant admission regardless of PSI class.
Age is the baseline for the PSI score because pneumonia mortality increases substantially with age. However, this means young patients with severe disease may be classified as low-risk. Always consider the full clinical picture.
PSI is typically calculated at initial presentation to guide the admission decision. It is not designed for serial reassessment during hospitalization. For tracking inpatient progress, use clinical stability criteria instead.
PSI does not capture social determinants of health, ability to take oral medications, oxygenation on room air vs. supplemental O2, multilobar infiltrates, immunosuppression severity, or the causative pathogen. These factors should be considered separately.