Tuberculin Skin Test

A Tuberculin (Mantoux) Skin Test (TB Skin Test) is performed to determine whether a person has been infected with the Tuberculosis (TB) bacteria. It tests for a latent TB infection, and not for an active TB disease. 

A Tuberculin (Mantoux) Skin Test (TB Skin Test) is performed to determine whether a person has been infected with the Tuberculosis (TB) bacteria. It tests for a latent TB infection, and not an active TB disease. 

Not all those infected with TB show symptoms or become sick. Two TB-related conditions exist, namely TB disease and latent TB infection (LTBI). Those with LTBI show no symptoms, do not feel sick, and cannot infect others. Those with TB disease must seek proper treatment as, when left untreated, the disease can be fatal. 

TB is caused by the Mycobacterium tuberculosis bacterium. TB is most known to attack the lungs but can attack any part of the body, including the brain, kidneys, and lungs. Symptoms of TB largely depend on where the TB bacteria grow. TB in the lungs can include symptoms including a severe cough, lasting 3 weeks or longer, chest pain, as well as coughing up sputum (phlegm from deep inside the lungs) or blood. Other TB symptoms can include weight loss, lack of appetite, fever, chills, night sweats, weakness, or fatigue.  


A Tuberculin (Mantoux) Skin Test (TB Skin Test), performed at Brintnell Pharmacy and Travel Clinic, is administered by injecting the inner surface of the forearm with a small amount (0.1ml) of tuberculin purified protein derivative (or PPD). The needle’s position during the injection is crucial. The bevel should face upward as an intradermal injection. When correctly placed, the injection results in a pale skin elevation (wheal) with a diameter of 6mm to 10mm. 

The result is read after 48 hours and not later than 72 hours after the injection has been administered by measuring the size of the firm swelling (induration) of the forearm if any. A negative test typically means that the person is not infected with the TB bacteria. A positive test typically means that the person has a latent TB infection. However, it can be the result of a TB vaccine (BCG) or a bacterial infection, like the Mycobacterium tuberculosis bacteria. 

If a person does not return within 72 hours of their test, they will need to be rescheduled for another skin test.  


Canada has one of the lowest infection rates globally, so knowing when you might need a TB skin test is essential. You should be tested for TB if you fall into one of the following categories:

  • Exposure: You have had contact with an infected individual. If the initial result is negative, a follow-up test 8-10 weeks later is recommended due to a potential reaction delay.
  • Travel: You have visited an area where TB is prevalent.
  • Healthcare: You work in a healthcare facility, laboratory, or other organization that deals with TB or TB patients.
  • HIV: You are living with HIV.
  • Immuno-Compromised: You are about to undergo a treatment that will weaken your immune system (e.g. treatments for autoimmune conditions like Crohn’s disease or rheumatoid arthritis).


  1. How Is TB Spread?

TB is spread through the air when an infected person coughs, sneezes or speaks. Persons nearby can inhale the bacteria and become infected in this way.

  1. What Are The Symptoms of TB?

Common symptoms of TB include persistent coughing (often with blood or mucus), chest pain, painful breathing, weight loss, being easily tired, fever, chills, and night sweats.

  1. What Is Latent TB?

The TB bacteria can live in your body without making you ill. In this case, the bacteria are dormant and are not multiplying. During latent TB, you can’t infect another person with the bacteria.

  1. How is TB diagnosed?

TB can be diagnosed through various tests, sometimes used in combination. The most common test is a TB skin test. Other options include blood tests, chest X-rays, and sputum samples (a mixture of saliva and mucus that has been coughed up) that can also be used to identify the bacteria.

  1. Is TB Treatable?

Yes, TB is treatable with antibiotics. The treatment usually involves a blend of antibiotics taken over several months. If you have a positive TB test result, your healthcare practitioner will discuss treatment options with you.


At Brintnell Pharmacy and Travel Clinic, we provide Tuberculin Skin Test (TB Skin Test) for health care students and employees. We have a pharmacist who has been trained to administer and interpret the TST.  

If you have a positive skin test result, you will be referred to a family doctor or Tuberculosis Services for a chest x-ray and possibly other tests.

Contact the friendly team at Brintnell Pharmacy today if you have any more questions about TB or need to book a TB skin test.