Don't worry

It is good if you have a record of vaccination in China. Don't worry, if you do not have one. Just before you file I-485, visit a doctor appointed by INS and request all what they need. Normally they will offer a list what you should do before you go to them. Bring the information to your primary care doctor and request a test if you had vaccinated any of them previously. Soon they will report what is positive and what is negative. Request a vaccination if you are negative of any kind. All the examination and vaccination could be covered by your insurance if you have a proper one. With the test report and the record of vaccination, you can formally visit an INS doctor for a TB test. If you are positive of TB, they will have your chest x-rayed. Then they will offer a report to INS in a sealed envelope. Of course, you can have a copy. The INS doctor will charge you at no more than $200 (Pennsylvania, not sure about other State), not covered by insurance.