I went to Mayo last March to get a diagnosis and plan after having CT’s suggesting MAC lung. I very seldom get out mucus and couldn't there. They sent me to Respiratory Therapy to try to get one using bronchodilator, 3% saline and 7%. I got a little blood out, but it was an inadequate speciman so they did a bronchoscopy and got a speciman from the R middle lobe. It did not grow out MAC. Btw, RT told me it was pretty common for patients to fail to get a sputum with induction if they produce little.