How is TB Diagnosed?

Skin Test (PPD): A testing solution is placed just beneath skin on your arm to see if a reaction (such as a hard, red bump) occurs. You will need to return to the office in 2 or 3 days to have your arm checked. Be sure to keep the appointment. You will learn the test results during the visit.


Blood Test: In this test, a small amount of blood is drawn and sent to a laboratory for testing. Your doctor can tell you whether this test is offered in you area.


Other Tests: If you have TB infection, other test, such as a chest x-ray, are needed to learn whether the infection is  is active. You doctor may also take a sample fo your sputum (mucus that comes up when you cough). The sample is sent to a laboratory and tested for TB bacteria. Knowing the type of bacteria causing your illness helps your doctor choose the right medication to treat the disease.


When you are tested for TB there are a three key things to remember:


  • First, the test is NOT a vaccine. This means that the shot that you are getting does not make you immune to the disease.
  • Second, The test is very quick and it should not hurt at all.
  •  Third and probably most important, you MUST come back to the place you got the shot within 48-72 hours to get it 'read'. Only a skilled nursing professional can read the test so you must come back or the first shot does not do any good.