How is the TST performed?
A TST involves a small injection of tuberculin (purified protein derivative) into the forearm. After a few days, a red mark or lump may appear, or there may be no change at all. A specialist TB nurse needs to look at the place where the injection was done 48-72 hours after the test.
Before you have a TST
There are some health conditions and medicines that can affect your test result. Tell your nurse or doctor if you:
- have any immune weakening illnesses such as HIV, cancer, or kidney disease,
- take medicine that affects your immune system such as steroids (e.g. prednisone), or chemotherapy (cancer drugs)
- have had a fever (>38° C) or infection in the past month, such as the flu, measles, or a chest infection,
- have received any vaccines in the past month,
- have had TB in the past, contact with someone with TB, have received the TB vaccine (BCG),
- have previously had a TST.
After you have a TST
- Do not scratch the injection site.
- Do not cover the site with any dressing, band aid, cream, or ointment.
- If any blisters occur do not break them.
- You may continue all normal activities including work, sports, bathing, and showering.
Make sure the injection site is looked at by a specialist nurse or doctor 48-72 hours after the TST was done so any reaction can be assessed and recorded. If the TST is positive, you may need some follow-up tests. The nurse or doctor will explain the result and whether any more tests or treatment is needed.
Further information
For more information visit Tuberculosis (TB) fact sheets.
For free help in your language, call the Translating and Interpreting Service on 13 14 50.
