PSI/PORT Score Calculator

How to Use This Calculator

1. Enter all 20 PSI variables (demographics, comorbidities, examination, labs, imaging).
2. PSI score, Risk Class I–V, 30-day mortality, and disposition display instantly.
3. Risk Class tab: enter score manually to check class and mortality.
4. PSI vs CURB-65 tab: compare both scores side by side.

Formula

Example

Frequently Asked Questions

• What is the PSI/PORT score? ▼
  The Pneumonia Severity Index (PSI), also known as the PORT (Pneumonia Patient Outcomes Research Team) score, is a validated clinical prediction rule developed by Fine and colleagues and published in the New England Journal of Medicine in 1997 to stratify patients with community-acquired pneumonia (CAP) into five risk classes based on 30-day mortality. The score incorporates 20 variables: age (women subtract 10 points from their age), place of residence (nursing home adds 10), three categories of comorbidities (neoplasm +30, liver disease +20, heart failure +10, cerebrovascular disease +10, renal disease +10), five physical examination findings (altered mental status +20, RR ≥30 +20, SBP <90 +20, temperature abnormality +15, pulse ≥125 +10), and seven laboratory/imaging abnormalities (pH <7.35 +30, BUN ≥30 mg/dL +20, sodium <130 mEq/L +20, glucose ≥250 mg/dL +10, haematocrit <30% +10, PaO2 <60 mmHg +10, pleural effusion +10). PSI Risk Classes: I (no comorbidities, age <50, normal exam) — 0.1% mortality; II (score ≤70) — 0.6%; III (71–90) — 0.9%; IV (91–130) — 9.3%; V (>130) — 27%. Classes I–III are suitable for outpatient management; Class IV requires brief hospitalisation; Class V requires inpatient care.
• When should I use PSI vs CURB-65? ▼
  The choice between PSI and CURB-65 depends on clinical setting, patient characteristics, and the primary decision being made. CURB-65 is preferred in emergency department triage, primary care, and situations requiring rapid risk stratification without comprehensive laboratory data. Its five criteria can be assessed in under one minute, making it practical for high-volume settings. PSI is preferred when the primary question is whether a patient can safely be treated as an outpatient — it has superior sensitivity for identifying low-risk patients (PSI Class I–II) who can be confidently discharged. The Fine et al. 1997 derivation and validation study showed PSI correctly identified 76% of low-risk patients who had 30-day mortality under 1%, whereas CURB-65 occasionally flags low-risk patients as moderate risk due to age alone. PSI is particularly recommended by IDSA/ATS 2019 guidelines for identifying patients who can avoid hospitalisation. However, PSI is burdensome in settings without full laboratory access: it requires BUN, electrolytes, blood gas, haematocrit, and blood glucose, as well as chest imaging review. When laboratories are limited or when rapid disposition is needed, CURB-65 performs adequately. Both guidelines (IDSA/ATS and BTS) endorse both scores; combining both tools reduces the risk of inappropriate triage.
• Why is PSI considered more accurate than CURB-65? ▼
  Multiple systematic reviews and meta-analyses have confirmed that PSI has superior accuracy to CURB-65 for predicting 30-day mortality and identifying low-risk pneumonia patients. The primary reason is that PSI incorporates a more comprehensive set of prognostic variables that capture disease severity, host vulnerability, and physiological derangement. Its 20-variable model with weighted points better reflects the multifactorial nature of CAP prognosis than the 5-variable CURB-65. Key advantages of PSI: (1) PSI assigns substantial weight to laboratory abnormalities (pH <7.35 = +30 points, BUN ≥30 = +20) that reflect physiological severity not captured by CURB-65. (2) CURB-65 assigns a full point for age ≥65, which means any elderly patient with no other risk factors automatically falls into "moderate risk" regardless of their clinical state — potentially inflating hospitalisation rates. PSI better adjusts for age while weighting comorbidities separately. (3) PSI Class I–II provides very high negative predictive value for mortality (<0.6%), enabling safe outpatient discharge. In Loke et al. meta-analysis (2011), PSI had area under the ROC curve of 0.81 vs 0.76 for CURB-65 for 30-day mortality. The trade-off is complexity and lab requirements. For admission decisions in young, healthy patients, PSI is more reliable; in elderly or nursing home patients, additional factors like functional status and social support must supplement both scores.
• What does PSI Class V mortality mean? ▼
  PSI Class V (score >130) identifies the highest-risk group of CAP patients, with an observed 30-day mortality of approximately 27% in the original Fine et al. derivation and validation cohort of 52,000 patients. This mortality rate is comparable to, or higher than, many forms of metastatic cancer. Class V patients typically combine high age, multiple comorbidities, and severe physiological derangements: they commonly have altered mental status, marked tachypnoea, hypotension, acidosis, elevated BUN, and hyponatraemia on presentation. Such patients require inpatient admission and, in many cases, ICU-level care. The ATS/IDSA severe CAP criteria (one major criterion — need for mechanical ventilation or vasopressors — or ≥3 minor criteria) help identify which Class V patients need immediate ICU admission rather than general medical ward care. Clinical management of Class V CAP: prompt IV antibiotics (ideally within one hour of diagnosis), two blood cultures before antibiotics, blood gas monitoring, fluid resuscitation for haemodynamic instability, supplemental oxygen targeting SpO2 ≥94%, and consideration of respiratory support. Steroids: dexamethasone 6 mg daily for 4 days reduces mortality in ICU-admitted CAP (CAPE-COD trial, 2023). Microbiological investigation is particularly important in severe CAP to guide de-escalation from empirical broad-spectrum coverage.
• Are there limitations of PSI in young patients? ▼
  PSI has a recognised limitation when applied to young patients, particularly those under 50 years of age: it tends to underestimate severity and risk in this group because age (and thus the largest single contributor to the PSI score) is low. A 30-year-old with severe bilateral pneumonia, hypoxaemia, and lactic acidosis may receive a PSI score below 70 (Class III or lower) simply because of their age, potentially suggesting inappropriately low-acuity management. This is the inverse problem of CURB-65 in the elderly: CURB-65 over-classifies elderly patients as moderate risk, while PSI under-classifies young patients as low risk. The practical implication is that PSI Class I–III in a young patient should not override clinical assessment — a young immunocompromised patient (HIV, asplenia, high-dose steroids), a patient with multilobar infiltrates, rapidly progressive respiratory failure, or a patient with SpO2 < 90% on room air warrants admission regardless of PSI class. IDSA/ATS guidelines explicitly state that severity scores should supplement, not replace, clinical judgement, particularly in immunocompromised patients where CAP is caused by atypical organisms (Pneumocystis jirovecii, Cryptococcus) not covered by standard empirical regimens. Additionally, PSI does not account for inability to tolerate oral medications, lack of social support, or rapid clinical deterioration — all important admission drivers in young patients.

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