Routine sputum culture
Routine sputum culture is a laboratory test that looks for organisms that cause infection. Sputum is the material that comes up from air passages when you cough deeply
How the Test is Performed
A sputum sample is needed. You will be asked to cough deeply and spit any material that comes up from your lungs into a special container. The sample is sent to a lab. There, it is placed in a special dish (culture). It is then watched to see if bacteria or other disease-causing organisms grow.
How to Prepare for the Test
Drinking a lot of water and other fluids the night before the test may make it easier to cough up the sputum.
How the Test will Feel
You will need to cough. Sometimes the health care provider will tap on your chest to loosen deep sputum. Or, you may be asked to inhale a steamlike mist to help you cough up the sputum. You may have some discomfort from having to cough deeply.
Why the Test is Performed
The test helps identify the bacteria or other type of germs that are causing an infection in the lungs or airways (bronchi).
In a normal sputum sample there will be no disease-causing organisms.
What Abnormal Results Mean
If the sputum sample is abnormal, the results are called "positive." Identifying the bacteria, fungus, or virus may help diagnose the cause of:
- Lung abscess
- Flare up of chronic obstructive pulmonary disease (COPD) or cystic fibrosis
There are no risks with this test.
Croft AC, Woods GL. Specimen collection and handling for diagnosis of infectious diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 63.
Limper AH. Overview of pneumonia. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia,Pa: Elsevier Saunders; 2011:chap 97.
Reviewed By: Daniel Levy, MD, PhD, Infectious Diseases, Lutherville Personal Physicians, Lutherville, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.