Mycobacterium tuberculosis bacteria may manifest in the human body in one of two forms: active TB disease or latent tuberculosis infection (LTBI). Individuals with TB disease are symptomatic and may spread the disease, while individuals with LTBI are asymptomatic and do not spread the bacteria.
Testing is an important component in the fight against tuberculosis. One-third of the world's population is estimated to have LTBI. Without treatment, up to 10% of these individuals will progress to active TB disease.
Two forms of testing are available: TST and IGRA blood tests. Limitations are present with each test method.
Recommended treatment regimens for LTBI are lengthy and may cause side-effects. Patient management during drug treatment includes periodic laboratory testing for liver enzymes. Smears and cultures for acid-fast bacilli may also be requested during this time.
