PSI Port Score Calculator
Stratify pneumonia severity using the Pneumonia Severity Index for disposition decisions. Enter values for instant results with step-by-step formulas.
PSI Port Score Calculator
Stratify pneumonia severity using the Pneumonia Severity Index (PSI/PORT score). Calculate risk class, 30-day mortality, and get disposition recommendations for community-acquired pneumonia.
Last updated: January 2026Reviewed by NovaCalculator Medical Editorial Team
Calculator
Adjust values & calculateDemographics
Comorbidities
Physical Exam
Lab / Radiology
Outpatient care. Low risk. Consider brief observation if clinical concern exists.
Formula
The PSI sums points from 20 variables: age in years (minus 10 for females), nursing home residence (+10), comorbidities (neoplastic +30, liver +20, CHF/CVD/renal +10 each), physical exam findings (altered mental status +20, RR>=30 +20, SBP<90 +20, temp abnormal +15, pulse>125 +10), and lab/radiology (pH<7.35 +30, BUN>30 +20, Na<130 +20, glucose>250 +10, Hct<30 +10, PaO2<60 +10, effusion +10).
Last reviewed: January 2026
Worked Examples
Example 1: Elderly Male with Multiple Comorbidities
Example 2: Young Healthy Female
Background & Theory
The PSI Port Score Calculator applies the following established principles and formulas. Health and medicine calculators are grounded in validated physiological measurement methods established through decades of clinical research. Body Mass Index, or BMI, is calculated by dividing weight in kilograms by height in meters squared (kg/m²), a formula originating from Adolphe Quetelet's 19th-century statistical work and later codified by the WHO into standard classifications: underweight below 18.5, normal weight 18.5 to 24.9, overweight 25 to 29.9, and obese at 30 and above. Basal Metabolic Rate quantifies the minimum energy required to sustain life at rest. The Mifflin-St Jeor equation, published in 1990 and widely regarded as the most accurate for most adults, calculates BMR as (10 × weight in kg) + (6.25 × height in cm) − (5 × age) ± sex adjustment. The older Harris-Benedict equations, revised in 1984 by Roza and Shizgal, remain in common use. Total Daily Energy Expenditure is derived by multiplying BMR by a physical activity factor ranging from 1.2 for sedentary individuals to 1.9 for extremely active ones, following the methodology validated by doubly labeled water studies. Body fat percentage can be estimated without laboratory equipment using the U.S. Navy circumference method, which uses neck, waist, and hip measurements, or via BMI-derived equations adjusted for age and sex. The Jackson-Pollock skinfold method offers higher precision with calipers. Blood pressure classification, according to the American College of Cardiology and the 2017 ACC/AHA guidelines, defines normal as below 120/80 mmHg, elevated as 120 to 129 systolic, and hypertension stage 1 as 130 to 139 systolic or 80 to 89 diastolic. Target heart rate zones for aerobic exercise are derived from maximum heart rate estimates, most commonly using the formula 220 minus age in years, with moderate-intensity training typically defined as 50 to 70 percent of maximum heart rate and vigorous intensity at 70 to 85 percent, consistent with CDC and American Heart Association guidelines. These thresholds guide safe and effective cardiovascular conditioning.
History
The history behind the PSI Port Score Calculator traces back through the following developments. The history of health measurement stretches back to ancient Greece, where Hippocrates around 400 BCE laid the foundation for observational medicine by systematically recording patient symptoms, diet, and environment. His humoral theory, though scientifically superseded, established the principle that the body operates as an interconnected system subject to measurable imbalance. The transformation toward modern medicine accelerated in the 19th century. Louis Pasteur and Robert Koch developed germ theory in the 1860s and 1870s, identifying microorganisms as disease agents and enabling targeted interventions. Florence Nightingale, working during the Crimean War in the 1850s, introduced statistical analysis to nursing practice, demonstrating through data visualization that sanitation reduced mortality. Her work is foundational to evidence-based health measurement. The discovery of vitamins in the early 20th century, beginning with Casimir Funk's coinage of the term in 1912 and culminating in the isolation of vitamins A through K, created the field of nutritional science and gave rise to dietary reference intake frameworks. The World Health Organization, founded in 1948, subsequently established global standards for health metrics, disease classification through the International Classification of Diseases, and recommended daily allowances. The BMI as a clinical screening tool gained traction in the 1970s through Ancel Keys' large-scale epidemiological work, which validated Quetelet's index as a population-level obesity indicator. Through the 1980s and 1990s, the Framingham Heart Study produced landmark data linking cholesterol, blood pressure, and lifestyle factors to cardiovascular disease risk, directly shaping the numeric thresholds still used in health calculators. The evidence-based medicine movement, formalized by Gordon Guyatt and colleagues at McMaster University in the early 1990s, demanded that all health recommendations derive from systematically graded clinical evidence. The digital health era beginning in the 2000s brought these formulas to consumer devices, wearable sensors, and smartphone applications, expanding access to health self-monitoring on a global scale and enabling population-level data collection that continues to refine clinical reference ranges.
Frequently Asked Questions
Formula
PSI = Age + Sex Modifier + Nursing Home + Comorbidities + Physical Exam + Lab/Radiology Findings
The PSI sums points from 20 variables: age in years (minus 10 for females), nursing home residence (+10), comorbidities (neoplastic +30, liver +20, CHF/CVD/renal +10 each), physical exam findings (altered mental status +20, RR>=30 +20, SBP<90 +20, temp abnormal +15, pulse>125 +10), and lab/radiology (pH<7.35 +30, BUN>30 +20, Na<130 +20, glucose>250 +10, Hct<30 +10, PaO2<60 +10, effusion +10).
Worked Examples
Example 1: Elderly Male with Multiple Comorbidities
Problem: A 78-year-old male nursing home resident with CHF presents with pneumonia. Altered mental status, RR 32, BP 85/50, temp 38.5C, pulse 130. Labs: BUN 35, Na 128, pH 7.30, PaO2 55. Pleural effusion present.
Solution: Age: +78\nSex (male): +0\nNursing home: +10\nCHF: +10\nAltered mental status: +20\nRR >= 30: +20\nSBP < 90: +20\nTemp (normal range): +0\nPulse > 125: +10\npH < 7.35: +30\nBUN > 30: +20\nNa < 130: +20\nPaO2 < 60: +10\nPleural effusion: +10\nTotal: 258 points
Result: PSI Score: 258 | Class V | Mortality: 27-31% | Hospitalize, consider ICU
Example 2: Young Healthy Female
Problem: A 32-year-old female with no comorbidities, no nursing home, normal mental status, RR 20, BP 120/78, temp 38.8C, pulse 96.
Solution: Age <= 50: Check Class I criteria\nNo comorbidities: Yes\nStable vital signs (no altered mental status, RR < 30, SBP >= 90, pulse <= 125): Yes\nMeets all Class I criteria
Result: PSI Class I | Mortality: 0.1% | Outpatient treatment with oral antibiotics
Frequently Asked Questions
What is the PSI/PORT score and how was it developed?
The Pneumonia Severity Index (PSI), also known as the PORT score (Patient Outcomes Research Team), is a clinical prediction tool developed by Dr. Michael Fine and colleagues in 1997 to stratify the severity of community-acquired pneumonia. It was derived from a cohort of 14,199 hospitalized pneumonia patients and validated in 38,039 additional patients across multiple institutions. The PSI uses 20 variables spanning demographics, comorbidities, physical examination findings, and laboratory or radiographic results to calculate a composite score. This score assigns patients to one of five risk classes that predict 30-day mortality, ranging from 0.1 percent in Class I to over 27 percent in Class V.
How are PSI risk classes defined and what do they mean?
The PSI divides patients into five risk classes based on total points. Class I includes patients age 50 or younger with no comorbidities and stable vital signs, assigned automatically without scoring. Class II includes patients with 70 points or fewer and has a mortality rate of approximately 0.6 percent. Class III encompasses scores from 71 to 90 with mortality of 0.9 to 2.8 percent. Class IV includes scores from 91 to 130 with mortality of 8.2 to 9.3 percent. Class V covers scores above 130 with mortality of 27.0 to 31.1 percent. Classes I through III are generally considered low risk and potentially suitable for outpatient management.
Which comorbidities does the PSI score include and how are they weighted?
The PSI assigns different point values to five specific comorbidities. Neoplastic disease, defined as any cancer except basal or squamous cell skin cancer that was active at diagnosis or treated within the past year, receives the highest weight at 30 points. Liver disease, including clinical or histologic diagnosis of cirrhosis or other forms of chronic liver disease, adds 20 points. Congestive heart failure, cerebrovascular disease, and renal disease each contribute 10 points. These comorbidities were selected because they independently predicted mortality in the original derivation cohort. Other conditions like diabetes or COPD are not included because they did not significantly predict 30-day mortality after adjustment.
How does the PSI score handle age and sex?
Age is the most heavily weighted demographic variable in the PSI score. For male patients, the age in years is added directly to the score, so a 75-year-old male automatically starts with 75 points. For female patients, 10 points are subtracted from their age before adding it to the score, reflecting the finding that women with pneumonia have slightly lower mortality than men of the same age. This means a 75-year-old female would contribute 65 points from the age component. The age adjustment reflects biological differences in pneumonia outcomes observed in the derivation cohort. Nursing home residence adds an additional 10 points regardless of sex.
What laboratory and radiographic findings are included in the PSI?
The PSI incorporates seven laboratory and radiographic findings, each weighted according to its prognostic significance. Arterial pH below 7.35 carries the highest weight at 30 points, reflecting the severity of metabolic derangement. Blood urea nitrogen above 30 mg/dL and serum sodium below 130 mEq/L each add 20 points. Glucose above 250 mg/dL, hematocrit below 30 percent, and arterial partial pressure of oxygen below 60 mmHg each contribute 10 points. Pleural effusion on chest radiograph adds 10 points. Not all labs need to be available; missing values are scored as absent, though this may underestimate severity in patients with incomplete workups.
How does PSI compare to CURB-65 for pneumonia assessment?
The PSI and CURB-65 are the two most widely used and validated scoring systems for community-acquired pneumonia severity assessment. PSI is more comprehensive with 20 variables compared to CURB-65 with only five, which makes PSI more complex to calculate but potentially more accurate. Research suggests PSI is better at identifying low-risk patients who can be safely treated as outpatients, while CURB-65 may better identify high-risk patients needing ICU care. PSI tends to classify more patients as low risk, potentially reducing unnecessary hospitalizations. CURB-65 is faster to calculate and does not require as many laboratory tests. Many guidelines recommend either tool and suggest choosing based on clinical context.
References
Reviewed by Rahul Singh, Health & Wellness Specialist · Editorial policy