Pneumonia : Investigations.

Investigations
CXR.
Oxygen saturation arterial blood gases if SaO2 <92% or severe pneumonia.
FBC, U&E, LFT, CRP, atypical serology.
Blood and sputum cultures.
Pleural fluid may be aspirated for culture.
Bronchoscopy and bronchoalveolar lavage if the patient is immunocompromised or on ITU.

Severity
Calculate the core adverse features "CURB-65" score:
Confusion (abbreviated mental test ≤8);
Urea >7mmol/L;
Respiratory rate >30/min;
BP <90/60mmHg).
Age >65

Score: 0-1 home treatment possible; 2 hospital therapy; >3 indicates severe pneumonia. Other features increasing the risk of death are: co-existing disease; bilateral/ multilobar involvement; PaO2 <8kPa/SaO2 <92%.