My father is suffering from fever from last 2-3 month, in 1998 he is suffering from TB but he completed his course of medicine. We thought he again having TB we done sputum for AFB which is negative we done sputum culture gram stain it's also negative, but one doctor after seen CT chest and x ray declared that he have TB again, so my question is is it possible that without sputum positive a person can be tb declared and what happens if he not having tb and we given tb dose to him ,is it harmful.