It can be hard to tell who is carrying the bacteria and is not sick (we call this colonized) from those with actual NTM disease. Diagnosis depends on:
- tests that show the NTM bacteria are there AND
- radiology (chest x-ray or CT scan) AND
- clinical judgement based on symptoms and other tests showing evidence of disease
Sputum (phlegm or mucous) is looked at under the microscope to see if NTM bacteria are there. Cultures are done to see if the bacteria grows. Some NTM grows within a few days, but some take several weeks to grow.
The best way to get a sputum sample is to cough out three early-morning sputum samples on different days. Sometimes, when samples are difficult to get or are unclear, a thin, flexible tube with a camera (a bronchoscope) may need to be inserted into your lungs to get samples. If other body parts are affected, fluids or tissues may also need to be collected.
Your health care provider will order other tests like a chest x-ray or a CT scan. Your health care provider will discuss which tests are best for you and what the results show. Repeat sputum cultures are usually done during treatment to see if the treatment is working.