PSI (Pneumonia Severity Index)
Calculate the Pneumonia Severity Index (PSI/PORT) score for community-acquired pneumonia mortality risk assessment. Enter demographics, comorbidities, exam findings, and lab values for risk class and charts.
Patient Demographics
Comorbidities
Physical Examination Findings
Laboratory & Imaging Findings
About This Calculator
The Pneumonia Severity Index (PSI), also known as the PORT score, is a validated clinical prediction tool that estimates 30-day mortality risk in patients with community-acquired pneumonia (CAP). Developed by Fine et al. and published in the New England Journal of Medicine (1997), the PSI scoring system helps healthcare providers make evidence-based decisions about patient disposition — whether to treat as an outpatient, admit for inpatient care, or transfer to the intensive care unit.
The PSI score incorporates 20 clinical variables across four domains: patient demographics (age, sex, nursing home residence), comorbidities (neoplasm, liver disease, CHF, cerebrovascular disease, renal disease), physical examination findings (altered mental status, respiratory rate, blood pressure, temperature, pulse, pleural effusion), and laboratory/imaging results (arterial pH, BUN, sodium, glucose, hematocrit, and arterial pO₂). Each variable contributes weighted points that sum to a total score, which determines the patient's risk class (I–V).
The PSI is widely used in emergency departments, internal medicine wards, and respiratory medicine units across the United States, United Kingdom, India, and other countries. It has been externally validated in diverse populations and healthcare settings. For low-resource settings, the simpler CURB-65 score is often preferred, but PSI offers superior discriminative power for identifying low-risk patients who can safely avoid hospitalization.
Important: This calculator is for educational and clinical reference purposes only. It does not replace professional medical judgment. Treatment decisions should consider the full clinical picture, including patient preferences, social support, and availability of follow-up care.
Frequently Asked Questions
What is the PSI score for pneumonia?
The Pneumonia Severity Index (PSI), also called the PORT score, is a validated clinical prediction tool that estimates 30-day mortality risk in patients with community-acquired pneumonia (CAP). It uses 20 variables across demographics, comorbidities, physical exam findings, and laboratory values to classify patients into five risk classes (I–V) with corresponding mortality rates from 0.1% to 31%.
How is the PSI score calculated?
The PSI score is calculated by assigning points for age (1 point per year), female sex aged under 70 (-10 points), nursing home residence (+10), and the presence of comorbidities: neoplasm (+30), liver disease (+20), CHF (+10), cerebrovascular disease (+10), renal disease (+10), along with physical exam findings: altered mental status (+20), respiratory rate ≥30/min (+20), systolic BP <90 mmHg (+20), temperature <35°C or ≥40°C (+15), pulse ≥125 BPM (+10), pleural effusion (+10), and laboratory findings: arterial pH <7.35 (+30), BUN ≥30 mg/dL (+20), sodium <130 mmol/L (+20), glucose ≥250 mg/dL (+10), hematocrit <30% (+10), and arterial pO₂ <60 mmHg (+10).
What are the PSI risk classes?
PSI has five risk classes. Class I (age ≤50, no risk factors, mortality 0.1%) automatically qualifies without point calculation. Class II (≤70 points, mortality 0.6%) and Class III (71–90 points, mortality 2.8%) are low to moderate risk typically managed as outpatients or with brief observation. Class IV (91–130 points, mortality 8.2–9.3%) requires inpatient hospitalization. Class V (>130 points, mortality 27–31.1%) requires ICU admission and aggressive management.
When should the PSI score be used instead of CURB-65?
PSI is more comprehensive than CURB-65, using 20 variables vs. 5, making it more accurate for classifying low-risk patients who can safely be treated as outpatients. However, PSI is more complex to calculate, requiring lab results. CURB-65 is simpler and faster for bedside use in emergency settings. In India and other resource-limited settings, CURB-65 is often preferred due to its simplicity, while PSI is commonly used in North America and Europe for more precise risk stratification.
Is the PSI score validated for use in India?
Yes, the PSI score has been validated in Indian populations. A study published in the Indian Journal of Chest Diseases & Allied Sciences (2010) evaluated the validity of PSI and CURB-65 in an Indian setting and found both scoring systems effective for predicting mortality in community-acquired pneumonia patients. The study recommended using these scores to guide hospitalization decisions in Indian clinical practice.
What is the difference between PSI and CURB-65?
PSI (Pneumonia Severity Index) uses 20 variables including age, comorbidities, physical exam findings, and lab values, classifying patients into 5 risk classes. CURB-65 uses just 5 criteria: confusion, urea >7 mmol/L, respiratory rate ≥30/min, low blood pressure, and age ≥65, giving a score of 0–5. PSI is more sensitive for identifying low-risk patients suitable for outpatient care, while CURB-65 is simpler and faster. Both predict 30-day mortality but PSI requires more data to calculate.
What PSI score requires hospitalization?
Patients with PSI Class IV (score 91–130) and Class V (score >130) generally require hospitalization. Class IV has a mortality rate of 8.2–9.3% and warrants inpatient care with IV antibiotics. Class V carries a mortality rate of 27–31.1% and strongly suggests ICU admission. Patients in Class I–III (score ≤90) are typically candidates for outpatient management or brief observation, depending on clinical judgment and social factors.
Is the PSI calculator free to use?
Yes, this PSI score calculator is completely free to use with no registration required. It provides instant risk classification, mortality estimates, and management recommendations. Save your results by sharing the URL, which preserves all input parameters for easy reference or consultation.