Pneumonia Severity Index (PSI/PORT)
What is the 30-day mortality risk in community-acquired pneumonia, and where should it be treated?
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About this tool
Twenty-variable prediction rule that assigns adults with community-acquired pneumonia to five risk classes for 30-day mortality, supporting site-of-care decisions.
Intended use
Adults with community-acquired pneumonia, to identify low-risk patients suitable for outpatient care.
Outcome
30-day mortality
Time horizon
30 days
Derivation population
14,199 adult inpatients (derivation); validated in 38,039 inpatients and 2,287 PORT patients.
Do not use in
Derived in community-acquired pneumonia; not intended for hospital-acquired pneumonia.
Limitations
- Age contributes heavily, so younger patients with severe physiology can be under-classified.
- Requires laboratory and arterial blood gas data for full scoring.
- Does not capture social factors, hypoxaemia severity beyond PaO₂ < 60 or inability to take oral therapy.
Clinical problems
Evidence
Evidence level
Strong evidence
Derived and externally validated in multiple cohorts (including prospective studies) and incorporated into major clinical guidelines. Methodology
Guideline status
Preferred over CURB-65 for site-of-care decisions in the 2019 ATS/IDSA CAP guideline.
Validation studies
MedisGroups inpatient cohorts and Pneumonia PORT inpatients and outpatients
No significant difference in mortality by class across three cohorts: class I 0.1–0.4%, class II 0.6–0.7%, class III 0.9–2.8%.
References
- Original publicationFine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med 1997;336:243-250. Find on PubMed (opens in a new tab)
- GuidelineMetlay JP, Waterer GW, Long AC, et al. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the ATS and IDSA. Am J Respir Crit Care Med 2019;200:e45-e67. Find on PubMed (opens in a new tab)
Version history
| Version | Formula | Effective | Reviewer | Changes |
|---|---|---|---|---|
| v1.0.0 | Fine 1997 point allocation and class rules | 2026-10-03 | — | Initial implementation with reference test vectors. |
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Clinical decision support only. Interpret results in the context of the individual patient and current guidance; HumanPulse does not replace professional medical judgment.