Some people do not produce enough sputum for a sample. Even though I usually produce copious amounts, there have been a few times when I had to go to the pulmonolgist's office, neb 10% saline, then have the RT to percussion clapping on my chest and back to get enough of a sample to culture.
Also, if the infection is only in the lower lobe, the sputum coughed up may not have enough MAC in it - even though x-rays clearly show cavities or nodules.
Sue

@terrim02 Trying to get a sputum from me is the definition of insanity- doing the same thing over and over and expecting a different result!! It has been tried unsuccessfully many times. And I have had MAC for many years. The only way it can be definitively diagnosed with me is with a bronch and most recently a minimally invasive robotic biopsy. After many years on Arikayce and the Big 3, I am now MAC free. I have a new gift - invasive aspergillosis fumagatos. They are now trying to figure a way to find out if the medicine for that is working after six months. Unfortunately, the minimally invasive procedure became incredibly invasive with a collapsed lung, chest tube, and chest hemorrhage. If there were a way to get this dried up old woman to spit up something I would have gladly done it. So for me the bronch was a necessary evil and not about doctors/hospitals and the almighty dollar. If you know of something besides the usual spitting techniques I’d be very interested. I’m seeing my lung surgeon in a few weeks to see what he can come up with besides a bronch. Irene5