Use this calculator to estimate the Pneumonia Severity Index (PSI/PORT) score for adults with community-acquired pneumonia. Enter age, sex, and any present risk factors below.
Educational tool only. Always combine score-based risk stratification with full clinical judgment, local protocols, and patient preferences.
What is the Pneumonia Severity Index (PSI)?
The Pneumonia Severity Index, also called the PORT score, is a validated clinical decision aid used to estimate mortality risk in adults with community-acquired pneumonia (CAP). It helps clinicians identify lower-risk patients who may be candidates for outpatient treatment and higher-risk patients who may benefit from hospitalization or intensive monitoring.
PSI is one of the most widely studied tools in CAP. It combines demographic factors, comorbid illness, bedside vital signs, and selected laboratory/radiographic findings into a single point score that maps to risk classes.
How this PSI calculator works
This calculator follows the classic PSI point model:
- Base points: Age in years (female patients receive age minus 10 points).
- Comorbid points: Added for diseases such as cancer, liver disease, heart failure, cerebrovascular disease, and renal disease.
- Exam and lab points: Added for abnormal vital signs and objective findings (for example high respiratory rate, low blood pressure, low sodium, acidosis).
After adding points, the score is converted into a risk class (I to V). In practice, this class supports—but does not replace—medical decision-making.
PSI risk class interpretation
| Risk Class | Total Points | Estimated Mortality | Typical Care Setting (Clinical Context Required) |
|---|---|---|---|
| I | Low-risk rule-out profile | ~0.1% | Often outpatient |
| II | ≤ 70 | ~0.6% | Usually outpatient |
| III | 71–90 | ~0.9–2.8% | Observation or brief inpatient stay |
| IV | 91–130 | ~8–9% | Inpatient treatment |
| V | > 130 | ~27–30% | Inpatient; high-intensity care often needed |
Why PSI is useful in clinical care
1) Objective risk stratification
PSI reduces reliance on “gut feeling only” by quantifying risk with a structured method.
2) Better triage decisions
For otherwise stable adults with low scores, PSI can support safe outpatient treatment plans and reduce unnecessary admissions.
3) Shared decision support
A transparent score helps clinicians explain risk to patients and families when discussing site-of-care options.
Important limitations
- PSI was designed for community-acquired pneumonia in adults and should not be blindly applied outside that context.
- It can underemphasize some social and practical factors (home support, adherence barriers, frailty, follow-up reliability).
- It does not replace immediate escalation for clear danger signs, sepsis, or rapidly worsening respiratory failure.
- Local antimicrobial resistance, access to outpatient follow-up, and clinician judgment are critical.
PSI vs. CURB-65
Both PSI and CURB-65 are common CAP tools. CURB-65 is simpler and faster, while PSI is more comprehensive and may classify low-risk patients with greater granularity. Many clinicians use both tools alongside bedside assessment rather than relying on either score in isolation.
Practical workflow tip
A practical sequence in many settings is:
- Confirm suspected CAP clinically and radiographically.
- Assess immediate instability (airway, oxygenation, perfusion, mental status).
- Apply PSI (and/or CURB-65) once key data are available.
- Decide disposition with clinical context, patient values, and system resources.
Final note
The PSI is a strong evidence-based tool for estimating mortality risk, but the best outcomes come from combining score-based medicine with thoughtful clinical care. Use this calculator as a structured aid—not a standalone diagnosis or treatment directive.