How It Is Done
Usually, the sputum sample is collected
early in the morning before you eat or drink anything. In some cases
(especially if you may have tuberculosis), three or more morning samples may be
If you wear dentures, you will need to remove them before
collecting a sputum sample. Then rinse your mouth with water, take a deep
breath, and then cough deeply to produce a sample of sputum. The health
professional collecting the sample may tap on your chest to help loosen the
sputum in your lungs before you cough. If you still have trouble coughing up a
sample, you may be asked to inhale an aerosol mist to help you cough.
Some people may need bronchoscopy to collect a sputum sample. During
bronchoscopy, a thin, lighted tube (bronchoscope) is inserted through your
mouth or nose into the airways leading to your lungs. You will be given
medicine that numbs your throat and nose so you do not feel discomfort from
the bronchoscope. You may also be given a sedative to make you sleepy during
the procedure. To collect the sputum sample, a salt solution may be washed into
the airway and then suctioned into a container. A small, thin brush may be used
to collect a sample.
A sputum sample can also be collected using
suction. During this procedure, a soft, flexible tube (called a nasotracheal
catheter) is inserted through the nose and down the throat. Suction is applied
for up to 15 seconds to collect the sputum sample. This method of collecting a
sputum sample is often used for people who are very sick or unconscious.
After a sample is collected
sputum sample is collected, it will be placed in a container with substances
(growth medium or culture medium) that promote the growth of infecting
organisms (bacteria or fungi). Bacteria usually need 2 to 3 days to grow. Fungus often takes a week or longer to grow. The organism that causes
tuberculosis may take 6 weeks to grow. Any bacteria or fungi that grow will be
identified under a microscope or by chemical tests. Sensitivity testing, to
determine the best antibiotic to use against the organism that grows, often
takes 1 to 2 more days.