Laboratory diagnosis of pneumonia

Laboratory techniques for the diagnosis of pneumonia are discussed. Gram's stain and culture of the sputum are still the most useful techniques for the diagnosis of bacterial pneumonia. Antigen detection can provide a rapid diagnosis and contribute to the initial choice of therapy in infections caused by Haemophilus influenzae, Legionella pneumophila, Chlamydia psittaci and Pneumocystis carinii.