Sputum Culture Test

It is most often used to find and diagnose bacteria or fungi causing an infection in the lungs or airways, see if a chronic lung illness has worsened, check if treatment for a lung infection is working, and help diagnose conditions like pneumonia, tuberculosis, and bronchiectasis.

Sputum is not the same as spit or saliva. Sputum is a thick type of mucus made in your lungs that contains cells from your immune system to help fight bacteria or other foreign substances.

Clear sputum usually means no infection, but large amounts may signal lung disease. White or gray may also be normal. Dark yellow or green often means a bacterial infection. Black is common in smokers or with black lung disease. Brown may indicate old blood. Pink can be a sign of pulmonary edema. Red may be an early sign of lung cancer or a pulmonary embolism.

It usually takes a few days to get the results of your sputum culture, but it may take weeks depending on the type of bacteria being tested for.

An abnormal result may mean you have a bacterial or fungal infection, such as pneumonia, bronchitis, or tuberculosis. It may also mean a flare-up of a chronic condition like cystic fibrosis or COPD.