If the Public Health System informs you that you’ve had contact with someone with active TB disease, you should see your doctor or call Public Health to arrange for the necessary tests
There are two kinds of tests that can identify latent TB infection — a skin test and a blood test.
The skin test is fast and simple. A small needle injects testing material, called tuberculin, under the skin. After the injection, you must return in 48 to 72 hours (2 to 3 days) to have the test read by a healthcare professional.
In some cases, a TB blood test is used instead of a skin test. The blood test measures how your immune system reacts to the germs that cause TB.
If you have a positive TB skin test or blood test, you may need other tests to determine whether you have active TB disease or latent (inactive) TB infection. An x-ray of your chest can show if your lungs have been damaged by TB. You may also be asked to provide samples of sputum (phlegm, pronounced “flem”) from deep in your lungs. These sputum samples will be tested in a laboratory to see if TB germs are in your lungs.
It’s important to know that if you have TB disease in your lungs or throat, you can pass it on to other people when you breathe, cough, speak, sing or sneeze. If you do pass the germ on to others, they can get sick, too. If tests show that you have active TB disease, you may have to be separated from other people at the beginning of your treatment, until lab tests show that you are no longer spreading TB germs.