Xray for chest is a medical procedure to detect such conditions in relation to lung problems such as PTB. It is a must for people to be CLEARED in order to secure that everyone is healthy enough and not a potential risk. They may deport, as I know, those who will fail the medical unless it is still treatable and not on a severe stage. Asthma, on the otherhand, is a chronic lung problem but not considered as contagious. Doctors will give "controls" (medications) for any episodes or attack. People with asthma still live a very normal life!---hope this help.