x-rays don’t guarantee no TB although there is usually some signs on an x-ray. If you’ve had TB I’m surprised that there was no scarring visible on the x-ray. The fact that you previously had TB would create concern that you may still have TB because there is so much drug resistant TB around and many stop their treatment because it is very tough to go through. Assume that is another reason you are being tested. Sputum test takes 2-3 months because they have to wait to see if anything grows from the sputum culture. If nothing grows from the culture the lung x-ray will then be repeated and if there are no changes or if it looks better than the first you will pass the TB part of the medical. If you have TB you are expected to get your TB treated which will take at least 6 months. You are not denied, your application is just put on hold until your treatment is over. Canada has very low TB levels and wants to keep it that way. TB is primarily limited to homeless people, people living on aboriginal reserves due to overcrowding and other social issues and refugees.
