A latent (inactive) tuberculosis (TB) infection is the
presence of TB bacteria in a person's lungs even though he or she does not have
symptoms of TB (such as coughing, weight loss, fatigue, or fever).
A person with latent tuberculosis infection has no signs of active TB on
a chest X-ray, and no TB-causing bacteria can be found in the mucus from the
person's lungs (sputum). The only proof that the person has a TB infection is a
positive TB skin test or TB blood test (interferon-gamma release assay or IGRA).
People who have a latent TB
infection do not spread the disease to other people. They may need to take
medicine to prevent the bacteria from becoming active in the future.
E. Gregory Thompson, MD - Internal Medicine & R. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology
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