Your doctor wants to collect some of the sputum ("phlegm") that you cough up from your lungs. The laboratory will test the sputum for tuberculosis (TB) germs.

Checking your sputum is the best way to find out if you have TB disease. If you are already taking medicine for TB, checking your sputum is the best way to tell if the medicine is working.

To be sure the test is accurate, you must cough up sputum from deep inside your lungs. Sputum from your lungs is usually thick and sticky. Saliva comes from your mouth and is watery and thin. Do not collect saliva.

Tip: If you cannot cough up sputum, try breathing steam from a hot shower or a pan of boiling water.

How to collect a sputum sample

Your doctor or nurse will give you a special plastic cup for collecting your sputum. Follow these steps carefully:

The cup is very clean. Don't open it until you are ready to use it.
As soon as you wake up in the morning (before you eat or drink anything), brush your teeth and rinse your mouth with water. Do not use mouthwash.
If possible, go outside or open a window before collecting the sputum sample. This helps protect other people from TB germs when you cough.
Take a very deep breath and hold the air for 5 seconds. Slowly breathe out. Take another deep breath and cough hard until some sputum comes up into your mouth.
Spit the sputum into the plastic cup.
Keep doing this until the sputum reaches the 5 ml line (or more) on the plastic cup. This is about 1 teaspoon of sputum.
Screw the cap on the cup tightly so it doesn't leak.
Write on the cup the date you collected the sputum.
Put the cup into the box or bag the nurse gave you.
Give the cup to your clinic or nurse. You can store the cup in the refrigerator overnight if necessary. Do not put it in the freezer or leave it at room temperature.