Routine sputum culture
Routine sputum culture is a test of secretions from the lungs and bronchi (tubes that carry air to the lung) to look for bacteria that cause infection.
How the test is performed
You will cough deeply and spit any sputum into a sterile cup. The sputum is then taken to the laboratory. There, it is placed in a special substance (medium) under conditions that allow the bacteria or fungi to grow.
How to prepare for the test
Drinking a lot of water and other fluids the night before the test may help to get the sample.
How the test will feel
You will need to cough. Sometimes the health care provider will tap on the chest to loosen deep sputum. There may be a steam-like mist to inhale to help you cough up the sample.
Why the test is performed
The culture is done on the sputum to help identify the bacteria that are causing an infection in the lungs or airways (bronchi).
In a normal sputum sample there will be no disease-causing organisms present.
What abnormal results mean
If the sputum sample is abnormal, the results are called "positive." Identifying disease-producing organisms may help diagnose:
Other conditions under which the test may be performed:
- Aspiration pneumonia
- Atypical mycobacterial infection
- Atypical pneumonia
- Coccidioidomycosis; acute (primary) pulmonary
- Coccidioidomycosis; chronic pulmonary
- Coccidioidomycosis; disseminated
- Disseminated tuberculosis (infectious)
- Histoplasmosis; acute (primary) pulmonary
- Histoplasmosis; chronic pulmonary
- Hospital-acquired pneumonia
- Mycoplasma pneumonia
- Pulmonary aspergilloma (mycetoma)
- Pulmonary aspergillosis; invasive type
- Pulmonary tuberculosis
- Viral pneumonia
What the risks are
There are no risks with this method of obtaining a sample.
Reviewed By: Daniel Levy, MD, Infectious Disease, Maryland Family Care, Lutherville, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.