My TB skin test came back positive… Now what?



When someone has a positive TB skin test, often their first question is “now what?”. After receiving positive results the first step is for the individual to get a chest x-ray to make sure there is not an active infection going on in the lungs. If the chest x-ray is clear and they are not having any symptoms, chances are the person has a latent TB infection. Latent TB means they have been exposed to someone with active TB and have the bacteria in their body, but it is not growing. Latent TB can not be spread to anyone.

Anyone with a positive skin test has the option of being treated for latent TB to reduce the risk of developing active TB. Treatment is usually 9 months long. It is estimated that once exposed and develop latent TB you have about a 10% life time risk of developing active TB (given that you have a healthy immune system). The risk is much higher for anyone with a low immune system.

If people decline treatment for latent TB, it is important for them to keep in mind the symptoms of active TB:

·         Bad cough lasting longer than 3 weeks
·         Pain in the chest
·         Coughing up blood
·         Weakness
·         Lack of appetite
·         Chills
·         Fever
·         Night sweats

If anyone with a history of a positive skin test develops any of these symptoms it is important that they contact their health care provider immediately.

For more information please call us at 519-355-1071 ext. 5902.
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About Author

Registered Nurse --- Vaccine Preventable Diseases


  1. I received the BCG vaccine in my birth country prior to moving to Canada. I never expected this would have such a huge impact in my life in Canada. Am a nursing student and have had to have the skin test and chest X rays at least once a year. Seems really redundant to me for such a testing protocol to be in place as my TST readings will always be a false positive and my chest X-ray have been clear each time. I wish the IGRA blood test could be used in clients who have received the BCG vaccine as its results are not affected by previous BCG vaccinations. And hopefully I would not need to be exposed to so much radiation. This is my dilemma as an immigrant and a nursing student. Do I have any other options that would not include annual chest X rays?