Tuberculin skin test

Also called the Mantoux skin test

Key points about the tuberculin skin test

  • A tuberculin skin test (Mantoux test) is used to find out if you have been infected by TB bacteria and have a TB infection, or latent TB (where you have TB bacteria that are dormant and not making you sick).
  • You can be infected by breathing in TB germs when in close contact with someone with TB or from being in places with higher rates of TB.
  • The test is done by injecting a small amount of tuberculin liquid into the top layer of skin on your arm.
  • It does not contain live bacteria and cannot give you tuberculosis (TB).
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You will be asked to have a tuberculin skin test to see if you have potentially been exposed to the TB bacteria. This could be if your doctor suspects you may have the disease and require treatment, or if you are at risk of catching it and need protection. 

You may be more at risk of getting TB if you:

  • are in close contact with a person with active TB disease
  • were born in a country with higher rates of TB
  • traveled to or lived for more than one month in a country with higher rates of TB
  • have a weakened immune system such as being HIV-positive
  • live or work in certain institutional settings, eg, healthcare facilities.

Read more about TB.

The tuberculin skin test involves having a small amount of liquid, called tuberculin, injected into the very top layer of the skin on your forearm. This is done with a small needle and syringe. The test, which is done by specially trained laboratory technicians, does not contain live bacteria and cannot cause TB.

  • You may get a small blister at the injection site, but this usually disappears within the first 30 minutes.
  • Sometimes the site may bleed a little and the nurse may cover it with a cotton wool swab. This can be removed after 10 minutes and discarded. 
  • Do not apply creams or band-aids to the injection site and avoid scratching it. To relieve an itchy reaction, apply ice or something cold. 

Graphic of TB skin test showing arm, needle and blister on skin


Image credit: Bruce Blausen Wikimedia Commons

After 2 to 3 days of having the tuberculin skin test, the laboratory technician will measure your skin’s reaction to the tuberculin. If more than 3 days have passed before you get the site checked, the assessment will not be reliable and you will need another skin test.

Interpretation of the test result depends on a number of factors, including whether you are known to have been in contact with somebody who has TB, whether you have previously had a BCG vaccine, your age and your medical history.

If your tuberculin test is negative, you may be advised to either:

  • have a repeat test in 1–2 weeks
  • have a BCG vaccination
  • have no further follow-up.

If your injection site shows a reaction, you may be advised to either:

  • have treatment for latent TB
  • have further tests for TB disease
  • avoid further tuberculin tests
  • consult with your usual doctor
  • have no further follow-up.

The following links have more information on the tuberculin skin test. Be aware that websites from other countries may contain information that differs from New Zealand recommendations.

Tuberculin skin testing(external link) Centers for Disease Control and Prevention, US, 2011
Tuberculin skin test(external link) Queensland Department of Health, Australia, 2013  

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Dr Ayesha Verrall, Senior Lecturer, Department of Pathology and Molecular Medicine, University of Otago, Wellington

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