I don't have MAC (knock on wood) but do have bronchiectasis and pseudomonas. I did not have pseudomonas at the time I saw an allergist for bad allergies but he automatically tested those IGA IGE IGM etc. tests. Later I saw an ID dr for the pseudomonas and she automatically ran those same tests so in some cases immunoglobulins will be checked by either an allergist or the ID dr and so there wouldn't be a real need for a separate immunologist unless maybe there was something really wrong in the tests. Just an observation.