Tuberculin Skin Test

A TB skin test (also known as Mantoux) 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.

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) can be performed at Brintnell Pharmacy and Travel Clinic. The staff at our TB skin test walk-in clinic will administer the test 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. This TB skin test reaction (it can look like a bruise) will be used to determine if the TB skin test is a negative or positive result.

For TB skin tests, negative results typically mean that the person is not infected with the TB bacteria. A TB skin test positive result 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.

A TB skin test false positive result can occur where the findings are positive but, in fact, the person is not infected. Several factors can lead to this, including:

  • Previous TB vaccination
  • Non-TB mycobacterial infection
  • Incorrect TB skin test reading
  • Cross-reactivity with other medications or medical conditions
  • A recent viral infection, for example, flu

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.

  1. How much does a TB skin test cost?

The cost of a TB skin test can vary depending on several factors, including your location and the specific TB skin test clinic you visit. Contact Brintnell Pharmacy and Travel Clinic today, and we will explain the test procedure and pricing.

  1. TB skin test: How does it work?

A TB skin test is a two-step process. Firstly, the injection will be administered to introduce a small amount (0.1ml) of tuberculin purified protein derivative. The second step is a waiting period of 48 (to a maximum of 72) hours. At this time, TB skin test negative or positive images can be determined, and the results can be shared with you.

  1. Does a TB skin test have side effects?

If the TB skin test reading results are going to be positive, then the injection site will become swollen and possibly itchy. Serious allergic reactions are rare. If you experience any unusual or severe side effects, contact Brintnell Pharmacy and Travel Clinic immediately.

Safety Tips From Your Friendly Pharmacist: Top TB Prevention Strategies

While the incidence of TB in Canada is extremely low, that doesn’t mean that you shouldn’t take precautions. This would be especially relevant if you will be visiting countries where TB is more common. Globally, millions of people are infected with TB bacteria, and while it is a treatable disease, there is a high mortality rate in countries that don’t have adequate health care.

Here are some top tips from your friendly pharmacists to try and prevent yourself from becoming a TB statistic.

  • Education and Awareness: It is crucial to raise public awareness about TB, its symptoms, and preventive measures. Educational campaigns can encourage individuals to take proactive steps in protecting themselves, their families and their communities.
  • Early Detection and Treatment: Early identification and treatment of TB cases are the most important ways of preventing further transmission. Individuals with symptoms such as persistent cough, weight loss, and night sweats should seek medical attention promptly. A TB skin test can be conducted to get a diagnosis. Early treatment will reduce the duration of infectiousness and thereby reduce the potential for transmission.
  • Good Hygiene Practices: Practicing good hygiene is one of the most important ways of preventing the spread of TB. Individuals who are infected with TB should make sure to cover their mouth and nose when coughing or sneezing, as the TB bacteria is transmitted through droplets in the air. Correctly disposing of tissues and handwashing protocols are also necessary.
  • Good Ventilation: The TB bacteria thrive in closed spaces with poor ventilation. Ensure your home and workspace is well-ventilated and preferably open to natural light. TB bacteria cannot survive in UV light.

Canada has an excellent public health system and is fully equipped to deal with the rare TB cases detected. Strategies such as screening for non-Canadians entering the country and ongoing monitoring and management of active cases all go a long way to prevent this disease from spreading.

PHARMACIST’S TIP: Where to Get a TB Skin Test

At Brintnell Pharmacy and Travel Clinic, we provide Tuberculin Skin Tests for healthcare students and employees. We have a pharmacist who has been trained to know how to administer and how to read the TB skin test.  

If you have a positive TB 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.