Hi Garry, did you get 9% or .9%? Tricky little decimal point! Point 9% is the normal amount of saline we have in our bodies and won't do much as far as causing your lungs to cough up sputum. 7% has seven times as much saline and comes in 4ml vials. I thought that 7% requires a prescription but someone recently said that you can get it in Amazon without a prescription.

The sputum sample will show if the antibiotics you are taking are working to kill your particular lung bacteria. They don't work for everybody and when they do work it some times takes a while before there is progress.

@garry I'm with Rita - if you got it locally without a scrip, you have.9% - if you want to kill MAC you need 7%. Current research shows 3% is not enough, even though it may be enough to bring up mucus - which is fine if you don't have MAC
As for the sputum sample, how was your MAC diagnosed?
First, a sputum culture is necessary to confirm MAC versus another infectious agent, and takes anywhere from 4-8 weeks to grow. When first diagnosed, there was so much MAC in my sputum that it was confirmed in 4 weeks, now it's still there but takes about 7 weeks to show. Second, the culture needs to be subjected to sensitivity testing to be sure the right drugs are being used. My docs use the state dept of health lab for the culture and National Jewish Health lab in Colorado for the sensitivity testing.
In my case, after the initial round of antibiotics, I wasn't producing much mucus, so I would neb with 10% saline to bring up sputum - believe me, it irritated mightily and got me coughing stuff up in minutes.
The point of sputum testing, in addition to initial diagnosis, is to determine how long to treat with antibiotics. Depending on the severity of bronchiectasis, and your other symptoms, typical treatment is 6-12 months after sputum no longer shows MAC. My case was a little different. After 18 months lung CT was clear and cough was rare and produced clear sputum, but MAC was still present. The long term antibiotics were taking a toll on body and life, so the doc stopped them, and I'm using 7% saline, hoping it will eradicate the bacteria, or at least keep more from growing.
I would never have known the questions to ask, or what to expect, without the support of this group. Here's hoping you get good results from your visit tomorrow.
Sue