My Dr. thinks that MAC might be colonized in my lungs. The first time I had heard of smears was last Wednesday. I asked my Dr. why we were not treating MAC. He said that I had a positive culture but a negative smear. I thought that they just did cultures on the sputum samples. The negative smear led him to believe that it might be a colonization. Before he does any treatment he is waiting on other sputum samples. I looked it up and smears are a quick result whereas a culture takes weeks to grow out. So I am still confused. I guess just have to send in more samples and wait on the results.