<s>[INST] hi i am 25 yrs old,55,and 54 kilos,.last april we had our anual pa, unfortunately my result turned out that suspiciuos lung density have seen in my xray so they required me to have an apicolordotic view. it turned out to be mild nodular hazy densities infiltrates my left upper lobe and ruled out to be ptb,,ptb class 3 as the doctor said. there is no history in our family with that sickness, but in my job i have a co employee who suffered from it,,my question doc is?how contagious i am at this point in time,how high is the risk that i can pass the bacteria?or what are the factors that can affect or to be consider so that i will be able to pass this. [/INST] Thanks for your question on Chat Doctor. I can understand your concern. I have gone through the x-ray report you have mentioned. This report is suggestive of left upper lobe infection. Most common cause for upper lobe infection is tuberculosis and pneumonia. So better to get done sputum microscopic examination to confirm this infection. This kind of infection spreads through coughing. Cough produces Chat Doctor.  So better to wear mask when coughing. First 2-3 weeks, person is contagious through coughing. So better to start treatment as soon as possible. After 2-3 weeks you will be not contagious to others. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks. </s>