PSI - Pneumonia Severity of Illness Scoring System


Patient Characteristic   Points assigned
Demographic factors Age:  Males age (in yrs)
            Females age (in yrs) -10
  Nursing home resident +10
Comorbid illnesses Neoplastic disease (active) +30
  Chronic liver disease +20
  Congestive heart failure +10
  Cerebrovascular disease +10
  Chronic renal disease +10
Physical examination findings Altered mental status +20
  Respiratory rate (RR) ≥30/minute +20
  Systolic blood pressure (BP) <90 mmHg +20
  Temperature (T) <35°C or ≥40°C +15
  Pulse (P) ≥125/minute +10
Laboratory and radiographic findings pH <7.35 +30
  Urea ≥11mmol/L or creatinine ≥120umol/L +20
  Sodium <130mmol/L +20
  Glucose ≥14mmol/L +10
  Hematocrit <30% +10
  PO2 <60mmHg or 02 sat <90% +10
  Pleural effusion on chest xray +10


Risk Class # of Points Mortality (%) Recommendations for Site of Care
I ≤50 yrs old with no comorbidities or listed abnormal physical findings 0.1 Outpatient
II 0-70 points 0.6


III 71-90 points 0.9 Generally outpatient
IV 91-130 points 9.3 Inpatient
V >130 points 27.0 Inpatient


Reprinted from Fine MJ, Auble TE, Yealy DM, et al.  A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med 1997; 336: 243-50


CAP severity PSI
Mild I or II
Moderate III
Severe IV or V