If you are applying for a visa to come to the UK for longer than six months, it is already a requirement for you to have a test at an approved clinic to show that you do not have active pulmonary tuberculosis (TB) if you are a resident of certain specified countries. You need to submit the TB certificate with your immigration application. From 30 April 2013, this requirement has been extended to include some visa categories where immigration permission of just six months may be granted, such as fiancé(e)s or proposed civil partners applying under the family rules that apply to non-points based system migrants.
If you are required to take a TB test and apply in India on or after 30 April 2013, the only clinic in Chennai that you can be screened for TB at is the The Apollo Heart Centre.
TB testing in India (includes list of acceptable test centres).