What does the PSI/PORT score predict?

It predicts 30-day mortality for adults with community-acquired pneumonia. The score sorts patients into five risk classes, from class I (very low risk, around 0.1 percent) to class V (high risk, often above 27 percent). It is mainly used to decide whether a patient can be safely treated at home.

How is PSI different from CURB-65?

CURB-65 uses just five variables and is fast at the bedside, while PSI uses twenty variables including comorbidities and lab results. PSI is more discriminating at the low-risk end, so it is better at confidently identifying patients who can go home, at the cost of being more time-consuming.

How is the age score calculated?

For men the age in years is added directly as points. For women, age minus 10 is used. This single term is usually the largest contributor to the total, which is why PSI tends to admit older patients.

What counts as Risk Class I?

Class I is a screening step: a patient under 50 with no listed comorbidity and normal vital signs and mental status is class I regardless of the point total. Everyone else is classed by their total points into II through V.

Can I use the score to override clinical judgement?

No. PSI is a decision aid, not a rule. Social circumstances, oxygen requirement, ability to take oral medication, and the clinician's overall impression can all justify admitting a low-class patient or, more rarely, treating a higher-class one at home.

Pneumonia Severity Index (PSI/PORT) Calculator

The Pneumonia Severity Index, also known as the PORT score, is a validated tool that estimates 30-day mortality in adults with community-acquired pneumonia and sorts them into five risk classes. Its main value is identifying low-risk patients who can be safely managed as outpatients, which reduces unnecessary admissions.

How it works

The score is the sum of weighted points across four groups of variables. Age is the foundation: for men the age in years is added directly, and for women age minus 10 is used. Points are then added for being a nursing home resident, for each comorbidity, for each abnormal physical finding, and for each abnormal lab or imaging result.

PSI total = age term
          + 10 (nursing home)
          + comorbidity points (cancer +30, liver +20, CHF/CVA/renal +10 each)
          + exam points (mental status +20, RR>=30 +20, SBP<90 +20, temp +15, pulse>=125 +10)
          + lab points (pH<7.35 +30, BUN +20, Na<130 +20, glucose +10, Hct<30 +10, PaO2 +10, effusion +10)

A separate screen identifies Risk Class I: a patient under 50 with no comorbidity and normal vitals is class I without needing the full tally.

Class bands and interpretation

The total maps to a class and an approximate mortality. Class II is 70 points or fewer, class III is 71 to 90, class IV is 91 to 130, and class V is above 130. Classes I and II generally support outpatient care, class III suggests brief observation, and classes IV and V usually warrant admission with class V prompting consideration of intensive care. Always weigh the result against oxygen needs, the ability to take oral antibiotics, and the patient’s home support before deciding on disposition.