回复：体检表被医生加了一句， X-ray发现有钙化点，推荐防御性治疗

Your case is different from "TB test 阳性，x-ray 正常". X-ray发现有钙化点 suggests you may have TB previously, but never been diagnosed and self-cured (if there was a TB patient in your family, contract TB was very easy). If you have never taken TB medicine, it is possible that few sleeping TB bacteria are still in your body, and may become active when you get old and have weak immune system (in this case, better take medicine now). Dependent on your family history, consult a TB expert.