Tuberculosis testing in China will extend to all longterm visa applicants on 31 December 2013.

From 31 December 2013, tuberculosis testing will extend to residents of China who wish to come to the UK for more than 6 months. Currently, testing only applies to those applying to settle in the UK but from 31 December this will extend to all other applicants coming to the UK for more than 6 months, including those coming to study or work.

If you plan to come to the UK for less than 6 months you do not need a TB test, unless you are applying for a 6 month fiancé(e) visa.
This passage explains whether you need to be tested for (TB) if you want to come to the UK from China. It also explains how you will be tested, and what to do if you test positive for TB.
Who needs to be tested?
If you are resident in China and would like to come to the UK for more than 6 months from 31 December 2013 you must be tested at an approved clinic and be free from tuberculosis before you apply for a visa. Currently, testing only applies to those applying to settle in the UK but from 31 December this will extend to all other applicants going to the UK for more than 6 months, including those going to study or work.
If you plan to come to the UK for less than 6 months you do not need a TB test, unless you are applying for a 6 month fiancé(e) visa.
If you are coming to the UK in any other visa category you currently do not need to be tested for tuberculosis.
Testing children
All children over 11 years old applying for a settlement visa must be tested for tuberculosis.
If you are a parent or guardian of children under 11 years old you must bring your children to an approved clinic and complete a health questionnaire. The clinician will then decide whether your child needs to be tested for tuberculosis. If the clinician decides not to test your child they will give you a certificate to say your child was not tested. This certificate must be submitted with your childs UK visa application.
All children under 16 years who are attending a clinic, must be accompanied by a parent or guardian and bring the items listed in the Attending the clinic section below.
Approved test clinics
You must be tested a clinic which has been approved by the Home Office.  We will not accept a tuberculosis test certificate from a clinic we have not approved.
Attending the clinic
You should contact one of the approved clinics to book an appointment. You should make it clear you need the test for a UK visa application. You can expect to get an appointment within a few days of your request.  We cannot arrange or prioritise appointments for you.
What you should bring with you:
proof of identification, which contains your photograph, such as your passport;
tuberculosis test fee; and if you have had tuberculosis in the past or have any other lung disease you should provide details of your previous screening and, if possible, your medical notes and x-ray results.
If you would like an appointment with a female clinician, please ask the clinic when you schedule your appointment.
If you need to cancel your appointment you should contact the clinic and refer to their cancelation policy and procedure.
What does the test involve?
You will be given a chest x-ray. You may need to remove your clothes from your top half for the x-ray. You will be given a gown to protect your modesty.
How long does the test take?
If the x-ray is inconclusive, you may be asked to give a sputum sample (phlegm coughed up from your lungs). Sputum test results can take up to 2 months to process.
Test fees
The fees for the chest X Ray will be 550 RMB. The test fee does not cover treatment if you have tuberculosis.
Getting your results
If you have the standard test your results and certificate should be available shortly from the clinic if:the Chest X-Ray is normal; and no TB investigation is required.
If the test results are inconclusive you may be required to take a sputum test (phlegm coughed up from your lungs). The results from this test can take up to 2 months to process.  If you do not have tuberculosis you will be given a certificate, which you should submit with your visa application.  The certificate is usually valid for 6 months.
You will not be issued with a certificate if you have been diagnosed with tuberculosis. The clinician will give you advice about treatment and provide you with a treatment referral letter. Treatment can take up to 6 months to complete. You will not be able to apply for a UK visa until you can show you have had treatment for tuberculosis and you are free from the disease.
In relation to your visa application the clinician will be specifically looking for evidence of tuberculosis.  You will be informed if any other abnormalities have shown up on the x-ray. You will be advised to contact your doctor for further tests.