Pathologist Questions Internist

How is tuberculosis diagnosed?

My daughter is starting school and I want to make sure she is protected from tuberculosis. I want to know how tuberculosis is diagnosed?

4 Answers

All schools need a tuberculin or PPD skin test. This determines whether a person has been exposed to TB. In some countries, BCG vaccines were given to the population. In such cases, there can be false-positive results. A chest-x-ray determines whether a disease is present.
In active cases, a sputum culture is necessary.
Tuberculosis is diagnosed by the tuberculin skin test, or PPD, or the Quantiferon Gold blood test. If either is positive, a chest xray will be required to determine if infection is active or latent.
The PPD skin test is a standard screening test. If it is positive, you have been exposed to TB. That would be followed by a chest X-ray.There are other confirmatory tests that are available. A culture of the suspected infection (e.g., a sputum culture) is the gold standard.

William Z. Cohen, M.D., FAAFP