What type of sample is typically collected for a sputum culture?

A sputum culture is performed to identify the presence of pathogens in the respiratory system, particularly in cases of suspected respiratory infections like pneumonia, tuberculosis, or bronchitis. The specimen for this test is collected from lung secretions, which consist of mucus produced in the airways and alveoli.

Sputum is specifically collected through the expectoration process; it reflects the condition of the lungs and lower airways. This type of sample is crucial because it provides valuable information about the microbial flora of the respiratory tract and assists in diagnosing infections or other lung diseases.

Blood samples, saliva, and skin swabs do not provide the necessary secretions related to the respiratory system that can indicate infections affecting the lungs. Thus, lung secretions are the appropriate and most relevant choice when conducting a sputum culture.