Tuberculosis (TB) Testing

TB Skin Testing at Lambton Public Health

Lambton Public Health only administers TB skins tests for medical purposes. Individuals must bring proper documentation from their healthcare provider. Contact Lambton Public Health to see if you qualify and to book your appointment.

We do not administer TB skin tests for employment, volunteer, or school purposes. 

Please check with your primary healthcare provider to see if they provide TB skin testing. Please also check with your workplace occupational health to see if they provide TB skin testing. All students needing a TST for educational reasons from Lambton College should contact the college directly to complete the test through the Student Wellness Center. 

Other TB Testing Locations


Bayshore Home Health Sarnia
49 Finch Dr. #8, Sarnia, ON N7S 5C6
(519) 383-6979

Family Health Team – Main Site
1150 Pontiac Dr, Sarnia, ON N7S 3A7

SMG Pharmacy
494 Christina St N, Sarnia, ON N7T 5W4
519-491-3434 or 905-741-8149
Fax: 519-491-0034


St. Clair Physician Group
233 Cameron St, Corunna, ON N0N 1G0
(519) 813-9800


The London Travel Clinic
1695 Wonderland Rd N Unit 2B, London, ON N6G 4W3

More Information about Tuberculosis (TB)

Inactive (latent) and Active Tuberculosis (TB) 

Inactive or latent TB occurs when a person has TB bacteria in their body (normally their lungs), but their immune system is able to prevent the bacteria from making them sick. The TB bacteria are essentially ‘sleeping’ in your body. During this time, the bacteria is not making you sick, and you’re not contagious to others (you can’t give TB to anyone else). 

Active TB occurs when a person has TB bacteria in their body (normally their lungs), and their immune system cannot stop the bacteria from making them sick. If a person has active TB, they are symptomatic and can pass the bacteria to other people.

Both latent and active TB are curable with antibiotics. TB treatment is free and accessible for all people through Lambton Public Health. 

For more information about tuberculosis symptoms and treatment, please visit: Tuberculosis: Symptoms and treatment –

TB Skin Testing 

A TB skin test is used to screen for tuberculosis. A TB skin test indicates if you have been exposed to TB (if the germ is in your body). It can not tell if you have active or inactive TB. If the skin test shows that the TB germ is in your body (the test is positive), a Public Health Nurse will arrange necessary follow-up care. 

For a skin test, you will have a small amount of non-infectious tuberculosis protein injected under the skin of your arm. This protein cannot spread the disease. It takes 48-72 hours for the skin to react to the injection. You will be scheduled for a follow-up appointment 2-3 days after your initial appointment so that a Public Health Nurse can read the test. You must be able to attend the follow-up appointment for it to be a valid test.

One-Step vs. Two-Step TB Skin Tests 

A one-step TB skin test includes injecting the protein under your skin and having it read 48-72 hours later. 

A two-step TB test is required to establish a baseline. An initial test is completed and reads in the 48-72 hour timeframe. If the initial test is positive, an additional TB skin test is not completed. If the initial test is negative, a second test is completed one to four weeks after your initial test and read again 48 hours later. 

If you have a documented two-step skin test, you will never have to have an additional two-step skin test. 

Positive TB Skin Tests 

A positive TB skin test could indicate that you have a TB germ in your body. If your skin test is positive, a Public Health Nurse will arrange follow-up investigations possibly including completing confirmatory blood work (IGRA), and or referring you to our respirologist (lung doctor) for treatment or monitoring options.