A sputum culture is a test to detect and identify bacteria[1] or fungi that infect the lungs or breathing passages.

[2] A sample of sputum is collected in a sterile, wide-mouthed, dry, leak-proof and break-resistant plastic-container and sent to the laboratory for testing.

For selected organisms such as Cytomegalovirus or "Pneumocystis jiroveci" in specific clinical settings (immunocompromised patients) a bronchoalveolar lavage might be taken by an experienced pneumologist.

The Infectious Diseases Society of America recommends that sputum cultures be done in pneumonia requiring hospitalization, while the American College of Chest Physicians does not.

Such pathogens include Streptococcus pneumoniae, Haemophilus influenzae and the highly infectious M tuberculosis, which are transmitted by inhaling aerosols.