PSI Port Score Calculator

The Pneumonia Severity Index estimates 30-day mortality in community-acquired pneumonia and exists mainly to answer a disposition question: can this patient be treated at home? Its structure is unusual among clinical scores because age in years is used directly as the point base, with 10 points subtracted for female sex, and everything else is added on top. Comorbidity weights reflect their independent mortality contribution, with neoplastic disease carrying the heaviest single weight at 30 points, liver disease 20, and congestive heart failure, cerebrovascular disease, and renal disease 10 each. Physical findings add altered mental status, respiratory rate at least 30 per minute, and systolic blood pressure below 90 mmHg at 20 points each, temperature below 35 or at least 40 degrees C at 15, and pulse above 125 at 10. Laboratory and radiographic items include arterial pH below 7.35 at 30 points, blood urea nitrogen above 30 mg/dL and sodium below 130 mmol/L at 20 each, and glucose above 250 mg/dL, hematocrit below 30 percent, PaO2 below 60 mmHg, and pleural effusion at 10 each. Totals map onto five risk classes with sharply different outcomes: Class I and II near 0.1 to 0.6 percent mortality and suitable for oral outpatient therapy, Class III at roughly 1 to 3 percent and often managed in observation, Class IV at about 8 to 9 percent requiring admission, and Class V above 27 percent with intensive care consideration. The main limitation is that age dominates the total, so a fit 85-year-old can land in a high class while a physiologically deranged 35-year-old is undertriaged. PSI also ignores social factors, oral intake, and hypoxia severity beyond a single PaO2 cut-off, so it should inform rather than dictate disposition.

The index came out of the Pneumonia Patient Outcomes Research Team, a project funded by the United States Agency for Health Care Policy and Research to reduce unwarranted variation in pneumonia admission decisions, which at the time ranged widely between hospitals for clinically similar patients. Michael Fine and colleagues at the University of Pittsburgh derived the rule from a large Medicare inpatient cohort and validated it in tens of thousands of inpatients plus a prospective cohort of inpatients and outpatients drawn from the PORT study sites. The results were published in the New England Journal of Medicine in 1997 under the title describing a prediction rule to identify low-risk patients with community-acquired pneumonia, and the tool is still often called the PORT score or the Fine score after that lineage. Because the 20-variable score requires arterial blood gas and several laboratory values, it proved cumbersome at the bedside, and the British Thoracic Society lineage produced the simpler CURB-65 rule in 2003 as a five-item alternative. Comparative studies since have generally found PSI better at identifying genuinely low-risk patients who can go home, while CURB-65 is faster and somewhat better at flagging the severely ill. The 2007 Infectious Diseases Society of America and American Thoracic Society joint guideline endorsed the use of a validated severity score, naming both, and the 2019 update continued to favor PSI for the outpatient decision. Later work added biomarkers such as procalcitonin and proadrenomedullin to PSI in research settings, but the original 1997 weights remain in routine use.