PSI / PORT Score Calculator (Pneumonia)

Q: What is the PSI or PORT score?

The Pneumonia Severity Index, derived from the Pneumonia Patient Outcomes Research Team cohort, which stratifies community-acquired pneumonia into five risk classes using twenty variables.

Q: How does PSI compare with CURB-65?

PSI uses far more variables and is better at identifying low-risk patients; CURB-65 uses five and is faster at the bedside. Many clinicians use CURB-65 for speed and PSI when a more careful outpatient decision is needed.

Q: Which PSI classes can be managed at home?

Classes I and II are generally considered suitable for outpatient treatment, and Class III for brief observation, provided social circumstances allow.

Q: Why does being female subtract ten points?

The derivation cohort found lower mortality among women at any given age, so the model applies a ten-point downward adjustment to reflect that observed difference.

Q: Does PSI apply to hospital-acquired pneumonia?

No. It was derived and validated in community-acquired pneumonia only; hospital-acquired and ventilator-associated pneumonia carry different risk profiles.

Calculate the Pneumonia Severity Index (PSI/PORT score) to stratify community-acquired pneumonia into five risk classes using demographics, comorbidities, examination findings, and laboratory results.

🫁 Clinical Score📐 PSI = age (−10 if female) + comorbidity + exam + lab points🏥 Health

Sex

Age (years)

Nursing home resident

Neoplastic disease

Liver disease

Congestive heart failure

Cerebrovascular disease

Renal disease

Altered mental status

Respiratory rate ≥ 30/min

Systolic BP < 90 mmHg

Temperature < 35°C or ≥ 40°C

Pulse ≥ 125/min

Arterial pH < 7.35

BUN ≥ 30 mg/dL

Sodium < 130 mmol/L

Glucose ≥ 250 mg/dL

Haematocrit < 30%

PaO2 < 60 mmHg or SaO2 < 90%

Pleural effusion on imaging

Please enter valid values.

Formula & Reference

Variable	Symbol	Formula	Units
PSI / PORT Score Calculator (Pneumonia)	—	PSI = age (−10 if female) + comorbidity + exam + lab points	points

Step-by-Step Examples

Example 1

Class I — Young and Well

42-year-old man, no comorbidities, normal vital signs and laboratory results.

Age under 50 with no additional points
Meets the Class I definition directly

✓ Class I — lowest risk, outpatient management

Example 2

Class III — Moderate

74-year-old woman with heart failure and a pleural effusion, otherwise stable.

Age 74, female → 74 − 10 = 64
Congestive heart failure → 10
Pleural effusion → 10
Total = 84

✓ Class III — 84 points

Example 3

Class V — Severe

81-year-old man from a nursing home, confused, RR 34, BUN 42, sodium 126, pH 7.28.

Age 81 → 81
Nursing home → 10, altered mental status → 20
RR ≥ 30 → 20, pH < 7.35 → 30
BUN ≥ 30 → 20, sodium < 130 → 20
Total = 201

✓ Class V — highest risk band

Real-World Applications

🫁

Pneumonia Disposition

PSI is the most extensively validated tool for deciding which pneumonia patients can safely be managed as outpatients.

🏥

Admission Avoidance

Identifying genuinely low-risk patients reduces unnecessary hospitalisation, cost, and hospital-acquired complication risk.

📊

Quality Benchmarking

Health systems use PSI class distribution to risk-adjust pneumonia outcome comparisons between sites.

📚

Respiratory Medicine Training

PSI and CURB-65 are taught together as complementary approaches to pneumonia severity assessment.

Common Mistakes to Avoid

⚠️

Treating PSI as purely a mortality predictor

PSI was designed to identify low-risk patients suitable for outpatient care. It is less useful at the severe end, where it can underestimate the need for intensive care in younger patients.

⚠️

Ignoring social circumstances

A patient may be Class II by score yet unable to manage at home due to frailty, isolation, vomiting, or inability to take oral medication. The score does not capture this.

⚠️

Underestimating risk in young patients

Because age contributes so heavily, a physiologically unwell 30-year-old can score deceptively low. CURB-65 or clinical judgement should complement PSI here.

Frequently Asked Questions

What is the PSI or PORT score? ▾

The Pneumonia Severity Index, derived from the Pneumonia Patient Outcomes Research Team cohort, which stratifies community-acquired pneumonia into five risk classes using twenty variables.

How does PSI compare with CURB-65? ▾