Doctors diagnose active
tuberculosis (TB) in the lungs (pulmonary TB) by using
a medical history and physical exam, and by checking
your symptoms (such as an ongoing cough, fatigue, fever, or night sweats).
Doctors will also look at the results of a:
Sputum cultureSputum culture. Testing mucus from the
lungs (sputum culture) is the best way to diagnose active TB. But a sputum culture can take 1 to 8 weeks to provide results.
Rapid blood tests help detect latent TB.3 They can help diagnose TB when results from a tuberculin skin
test are uncertain. These tests also can tell if a person who has had a
BCG vaccination has a TB infection. A rapid test
requires only one visit to the doctor or clinic, instead of two visits as
required for the tuberculin skin test. Rapid blood tests are also called interferon-gamma release assays (IGRAs).
Diagnosing TB outside the lungs
Diagnosing TB in
other parts of the body (extrapulmonary TB) requires more
testing. Tests include:
BiopsyBiopsy. A sample of the affected area is taken out
and sent to a lab to look for