Applicants who reside in certain listed countries and want to come to the UK for more than six months require a certificate to show that they are free from infectious pulmonary tuberculosis (TB). The list of countries is subject to change.
You do not need to apply for a TB certificate if:
You must get the TB test done at a Home Office approved clinic. The TB test is a chest x-ray.
If your TB test is clear, you will be given a certificate to confirm this. The certificate will be valid for six months. You must include the certificate with your visa application – failure to do so will result in your visa application being refused.
You should also carry the certificate in your hand luggage in case you need to show it to an immigration officer on arrival in the UK.
For further information see the Home Office website.