π« PSI Pneumonia Severity Index
PORT score: admit or treat at home?
For informational purposes only, not medical advice. Consult a healthcare professional.
The Pneumonia Severity Index, from the PORT study by Fine and colleagues, predicts 30-day mortality in community-acquired pneumonia using 20 variables. It sorts patients into five risk classes: class I and II carry under 1 percent mortality and are usually treated at home, class III around 1 to 3 percent is the judgment zone, and classes IV and V at roughly 9 and 27 percent are admitted. Emergency departments use it to make the admit-versus-home decision objective and consistent. This calculator reproduces the score for education and clinical reference.
How to Use This Calculator
Enter age and sex, then check every PORT variable present from history, exam, labs, and imaging. The total maps to a risk class with admission guidance.
Enter age in years. Age is the biggest single contributor: men add their age, women subtract 10.
Check comorbidities, vital-sign abnormalities, and lab/imaging findings. Each carries its validated point weight.
Read the risk class I to V. Classes I to III generally support outpatient care; IV and V point toward admission.
How the Math Works
Men add their age in years; women add age minus 10. Nursing home residence adds 10. Comorbidities add 30 for neoplastic disease, 20 for liver disease, and 10 each for heart failure, cerebrovascular disease, and renal disease. Exam findings add 20 each for altered mental status, respiratory rate 30 plus, and systolic under 90; 15 for extreme temperature; 10 for heart rate 125 plus. Labs and imaging add 30 for pH under 7.35; 20 each for BUN 30 plus and sodium under 130; 10 each for glucose 250 plus, hematocrit under 30, hypoxemia, and pleural effusion. Classes run I at 50 or below, II 51 to 70, III 71 to 90, IV 91 to 130, V above 130.
Worked Example
A 68-year-old man with heart failure scores 78 points, landing in Class III with expected mortality around About 0.9-2.8%%. That is the classic class III judgment zone: many such patients go home with close follow-up if they look well and support is good, while concerning exams or poor follow-up push toward admission. One comorbidity moved him from class II into class III, which shows why the history matters as much as the vitals.
Reading Your Result
Classes I and II are low risk and usually managed as outpatients with oral antibiotics. Class III is moderate risk where the decision hinges on the whole picture: oxygen needs, ability to take oral medicines, and follow-up reliability. Classes IV and V are high risk and generally admitted, with class V carrying roughly one-in-four mortality. The score guides disposition; it never overrides hypoxia, inability to swallow, or a clinician gut feeling that the patient looks sick.
| Class | Points | Mortality | Usual disposition |
|---|---|---|---|
| I | 0-50 | 0.1-0.4%% | Outpatient |
| II | 51-70 | 0.6-0.7%% | Outpatient |
| III | 71-90 | 0.9-2.8%% | Judgment zone |
| IV | 91-130 | 8-9%% | Admit |
| V | 130+ | 27-31%% | Admit, consider ICU |
Limitations
PSI predicts mortality, not the need for admission per se: a low-risk patient who cannot swallow or has no home support still gets admitted. It was derived in US emergency departments for community-acquired pneumonia and fits poorly for hospital-acquired pneumonia or immunocompromised hosts. Twenty variables invite missing data; the score is only as complete as the workup. Clinical judgment stays senior to the total.
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For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
What is the PSI PORT score?
The Pneumonia Severity Index from the Pneumonia Patient Outcomes Research Team study: 20 weighted variables predicting 30-day mortality in community-acquired pneumonia. It defines five risk classes that guide whether patients are treated at home or admitted. Published by Fine et al. in 1997, it remains the most validated pneumonia disposition tool.
What PSI score means admission?
Roughly: classes I and II (70 and under) go home, class III (71-90) is the judgment zone, and classes IV and V (above 90) are admitted. The score informs the decision; oxygen requirements, frailty, and follow-up reliability can override it in either direction.
How is PSI different from CURB-65?
PSI uses 20 variables and predicts mortality precisely; CURB-65 uses 5 bedside variables and is simpler to remember. PSI is better validated for the admit-versus-home decision, while CURB-65 shines for quick ICU triage. Many clinicians know CURB-65 by heart and calculate PSI when the decision is close.
Why do women subtract 10 points?
Because in the derivation cohort, women had lower pneumonia mortality than men at the same age, and the minus-10 adjustment fit the data. It is an empirical correction, not a biological claim about every woman. The score is a prediction model, and this term improved its predictions.
What mortality does each class carry?
Approximately: class I 0.1-0.4%%, II 0.6-0.7%%, III 0.9-2.8%%, IV 8-9%%, V 27-31%%. The steep jump between III and IV is why 90 points is the practical admission line. These are cohort averages; individual risk varies.
Can a low PSI patient still be admitted?
Yes, and often should be. The score does not see inability to take oral antibiotics, no caregiver at home, active vomiting, or concerning hypoxia that has not yet triggered the point thresholds. Disposition is a clinical decision the score informs, not one it makes.
Does PSI work for hospital-acquired pneumonia?
No. It was derived for community-acquired pneumonia in emergency departments. Hospital-acquired and ventilator-associated pneumonia involve different organisms, sicker hosts, and different risk drivers. Applying PSI there is outside its evidence.
What counts as neoplastic disease in the score?
Active cancer, generally within the past year or currently under treatment, scoring 30 points. A remote cured cancer does not count. The weight reflects how strongly active malignancy predicted mortality in the derivation data.
Why does BUN matter so much?
BUN 30 or higher adds 20 points because it marked dehydration, catabolism, and renal strain in the study population, all mortality predictors. It is one of the few lab values with heavy weight, alongside low pH and low sodium.
Is PSI or clinical judgment better?
Together. Studies show the score plus judgment beats either alone: the score catches risk factors humans underweight, like age and BUN, while judgment catches what the score cannot see. The best departments use PSI as the starting point of the disposition discussion, not the end.