@ellenn I've coughed up about 2-3 TBS blood twice over the past 3 years (a combination of red blood and clots). The first time was while I was swimming laps. I went to the ER because I was scared, and that, eventually, led (after about 1 ½ yrs) to the diagnosis of bronchiectasis and MAC. The second time I was in another state from my infectious disease (ID) doctor, so she suggested I go to my GP there and have her check my vitals, especially my oxygen levels. They turned out to be fine and I felt fine except for the blood. When I reported bac to my ID doctor, she told me not to worry. I now have a pulse oximeter to check my own oxygen leve. I cough in the mornings, but don’t really have any other symptoms and don’t take any antibiotics. I exercise/walk 2-3 miles daily.
I've been investigating whether coughing up blood may actually be a good thing in MAC. In my reading of MAC articles, I found one called "Retrospective study of the predictors of mortality and radiographic deterioration in 782 patients with nodular/brochiectatic MAC lung disease" by Gochi et al. (https://www.ncbi.nlm.nih.gov/pubmed/26246077 ) From the article, very few people seemed to die of MAC-related issues. The women with bloody sputum fared the best. I've been trying to find out why.