A TB skin test is a simple way to find out if you have latent/inactive TB. A small needle will be used to inject a small amount of liquid called tuberculin just under the skin on your arm.
You must return to the health unit 2 days after the test is given to have your arm checked, even if your arm looks okay to you.
Elgin St. Thomas Public Health offers weekly drop-in TB skin testing clinics:
Elgin St. Thomas Public Health
1230 Talbot St. St. Thomas, ON
Mondays from 9:30 am - 12:30 pm
Wednesdays from 1:30 pm - 4:00 pm
For more information on TB skin tests or alternative testing locations, call the health unit at 519-631-9900
TB skin tests are $40 per step ($80 for a two-step). Cash or debit only.
TB skin tests are free for people who are:
- contacts of an active case of TB;
- undergoing treatment or have a medical condition that makes them more likely to develop active TB;
- new to Canada and need the test for immigration medical surveillance;
- required to have a TB skin test by an educational institution for admission or continuation in a day care or pre-school program, or a program of study in a school, community college, university or other educational institution.
A two-step skin test means that you need two TB skin tests. The second test should be given 1 - 4 weeks after the first. The 2-step skin test needs to be done ONCE only and never needs to be repeated.
A two-step test is recommended for people who will need repeat TB skin tests in the future (e.g. health care providers).
A TB skin test is “positive” if there is a certain size bump where the fluid was injected. This means you might have TB germs in your body. Most people with a positive TB skin test have latent/inactive TB infection. Your health care provider will examine you and send you for a chest x-ray after a positive TB skin test. You may need other tests to see if you have active TB disease
- There may be slight swelling, redness, bruising or itching at the site, this is normal.
- Do not cover the test site with a bandage.
- Be careful not to rub or scratch the test site. If the area itches put a cold cloth on it.
- You can wash your arm and dry it gently.
- Anyone with a history of a positive TB skin test in the past;
- Anyone who has been diagnosed or treated for active or latent TB in the past;
- Anyone who has had a live vaccine must wait 4 weeks before having the TB skin test;
- Anyone who has had a recent major viral illness in the past month;
- Anyone who has had an allergic reaction to the TB skin test in the past.
The following are NOT contraindications for TB skin testing: pregnancy, breastfeeding, past history of BCG vaccination, vaccination with a non-live vaccine in the past 4 weeks or treatment with low-dose steroids.