I'm a bit confused because all the tests like the Mantoux, AFB sputum culture, and Genexpert sputum have come back negative, but the CT scan and x-ray are showing something concerning. We've done the AFB sputum test twice with a good sample, and it's negative both times. However, there's still a light cough, but the saliva seems normal. What could be causing this? Should we be worried or consider any other possibilities? Would appreciate any advice you can offer.