Investigations
May show more extensive abnormalities than physical examination would suggest.
infiltrates
Should be done for patients requiring hospitalisation. Relatively minor elevations in WBC counts (usually <13,000 x 10⁹/L [13,000/microlitre]) in patients with pneumonia suggest an atypical pathogen.
may be slightly elevated; may reveal relative lymphocytosis if infection is viral
May accompany Mycoplasma pneumoniae infections.
may show anaemia
Ordered for inpatients; elevated LFTs suggest Mycoplasma pneumoniae or Legionella pneumophila.
elevated
Low saturation indicates a more severe course of disease requiring hospitalisation.
may be low (<90%)
Elevation in urea suggests more severe disease favouring hospitalisation.
70.7 mmol/L (>198 mg/dL)
Indicated in cases of severe pneumonia and when L pneumophila infection is suspected.
may be positive with Legionella angtigen
Indicated in cases of severe pneumonia and when L pneumophila infection is suspected.
may be positive with Legionella
Either from sputum or throat swabs.
may be positive with M pneumoniae or C pneumoniae
Requires blood from early in the course of disease and a second blood specimen at least 10 days later. May be used to confirm diagnosis of many atypical pathogens and some viruses. In most cases, serology will be the main diagnostic test for Coxiella burnetii pneumonia.[35]
rise in titre on convalescent serum
Viruses can cause atypical pneumonia but may be difficult to culture and results may take days to return.
may be positive with viral pneumonia
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