Table 1.

2007 Infectious Diseases Society of America/American Thoracic Society Criteria for Defining Severe Community-acquired Pneumonia

Validated definition includes either one major criterion or three or more minor criteria

Minor criteria

Respiratory rate ≥ 30 breaths/min

PaO2/FiO2 ratio ≤ 250

Multilobar infiltrates

Confusion/disorientation

Uremia (blood urea nitrogen level ≥ 20 mg/dl)

Leukopenia* (white blood cell count < 4,000 cells/μl)

Thrombocytopenia (platelet count < 100,000/μl)

Hypothermia (core temperature < 36°C)

Hypotension requiring aggressive fluid resuscitation

Major criteria

Septic shock with need for vasopressors

Respiratory failure requiring mechanical ventilation

^*Due to infection alone (i.e., not chemotherapy induced).