Primary care
TB testing
For a job, a placement, a school, or immigration paperwork. There are two tests and they are not interchangeable — which one you need depends on you.
The two tests
The skin test — a small injection into the forearm, then a second visit 48 to 72 hours later so the result can be measured. It has to be read in that window; miss it and the test has to be repeated. Some employers require a two-step version, which means the whole thing twice, one to three weeks apart.
The blood test — one blood draw, no return visit. It is not affected by the BCG vaccine, which is the reason it is often the better choice.
If you had BCG as a child — standard in most of the world outside Canada and the United States — the skin test can read positive because of the vaccine. The blood test does not have that problem.
Ask what your form actually requires
Some employers, schools and agencies specify one test, and some specify the two-step skin test in particular. Bring the paperwork, because being told at the end that the wrong test was done is the commonest bad outcome here and it is entirely avoidable.
How it will go
Bring the requirement
Whatever your employer, school or agency has asked for, in writing if you have it. That decides which test.
The test
Either a small injection in the forearm, or a single blood draw collected in the building.
Reading it
A skin test needs you back at 48 to 72 hours — we will book that slot before you leave rather than leave it to you. A blood test needs no return visit.
The paperwork
Signed and completed properly for whoever asked. If the result needs following up, that happens here rather than being handed back as your problem.
If the result is positive
A positive test usually means latent TB — the bacteria are present but dormant, you are not ill and you are not infectious. It is common, and it is treatable.
The next step is a chest X-ray and an assessment to distinguish latent from active disease. That is arranged from here rather than left to you, and treatment for latent TB is a conversation about whether and when, not an emergency.
What it costs
Where TB testing is for medical reasons it is generally covered by OHIP. Where it is required by an employer, a school or an immigration process, it is an uninsured service like any other third-party requirement.
The fee schedule will be published here before we open, and you will be quoted before the test is done. See physicals and forms for how uninsured services work here generally.
Common questions
I missed my 48-hour reading window.
The test has to be repeated. Annoying but not harmful. If your week makes that window hard, say so at the start — the blood test may simply be the better option for you.
Can I get the blood test instead if my form says skin test?
Only if whoever is asking accepts it. Many do, some do not. Worth checking before the appointment rather than after.
Does a positive test mean I’m contagious?
Almost always no. A positive test on its own indicates exposure, not active disease. Distinguishing the two is exactly what the follow-up is for.