A TB skin test is the most common way to find out if you have TB infection.
New blood tests such as QuantiFeron-TB Gold, and Elispot are now approved or undergoing testing. These, too, can be used in certain circumstances to detect infection by Mycobacterium tuberculosis. You can get skin tested at the health department or at your doctor's
office. You should get tested for TB if you have spent time with
a person with infectious TB you have HIV infection or another
condition that puts you at high risk for TB disease you think:
A health care worker can give you the TB skin test. He or she
will inject a small amount of testing fluid (called tuberculin)
just under the skin on the lower part of your arm. After 2 or
3 days, the health care worker will measure your reaction to the
test. You may have a small bump where the tuberculin was injected.
The health care worker will tell you if your reaction to the test
is positive or negative. A positive reaction usually means that
you have TB infection.
If the healthcare worker takes your blood for testing the results will be available for the lab in few days.
If you have a positive reaction to the skin test, your doctor
or nurse may do other tests to see if you have TB disease. These
tests usually include a chest x-ray and a test of the phlegm you
cough up. Because the TB bacteria may be found somewhere besides
your lungs, your doctor or nurse may check your blood or urine,
or do other tests. If you have TB disease, you will need to take
medicine to cure the disease.
If you have recently spent time with someone with infectious
TB, your skin test reaction may not be positive yet. You may need
a second skin test 10 to 12 weeks after the last time you spent
time with the infectious person. This is because it can take several
weeks after infection for your immune system to be able to react
to the TB skin test. If your reaction to the second test is negative,
you probably do not have TB infection.
on people Who Can Benefit From Testing