What is it?

Sputum (say "SPYOO-tum") is a thick fluid, or mucus, made in the lungs and in the airways leading to the lungs. A sputum culture tests a sample of sputum to see if it contains germs. The sputum is placed in a container with substances that help germs grow.

Why is this test done?

A sputum culture is done to find and identify bacteria that are causing a lung infection such as pneumonia or tuberculosis. The culture can also find the best antibiotic to treat the infection. And it can check to see how treatment is working.

How do you prepare for the test?

If your sputum sample will be collected at home or in your doctor's office, don't use mouthwash. If bronchoscopy will be used to collect your sample, your doctor will tell you when to stop eating and drinking. Follow all of your doctor's instructions exactly. Tell your doctor if you have recently taken antibiotics.

How is the test done?

• To give a sputum sample at home or your doctor's office, you will need to remove your dentures if you wear them. Rinse your mouth with water. Then take a deep breath and cough deeply to produce a sample of sputum.
• If you are having trouble coughing up a sample, you may be asked to inhale an aerosol mist to help you cough.
• You may need a bronchoscopy to collect a sputum sample. A thin, lighted tube (bronchoscope) will be inserted through your nose or mouth into the throat and then into the airways leading to the lungs. To collect the sample, a salt solution may be washed into the airway and then suctioned into a container.

How long does the test take?

• The test will take a few minutes.

What happens after the test?

• You will probably be able to go home right away.
• You can go back to your usual activities right away.
• Your throat may feel sore if you had bronchoscopy or if the sputum was collected using a nasotracheal catheter.