Tuberculosis (TB) is an infectious disease caused by various strains of mycobacteria, usually Mycobacterium Tuberculosis, which is spread from person to person through the air when an infected person coughs, sneezes or otherwise transmits saliva through the air. While the disease typically attacks the lungs, it can also affect other parts of the body. However, not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and TB disease.

Persons with latent TB infection do not feel sick and do not have any symptoms. They are infected with M. tuberculosis, but do not have TB disease. Overall, without treatment, about 5 to 10% of infected persons will develop TB disease at some time in their lives. About half of those people who develop TB will do so within the first two years of infection. For persons whose immune systems are weak, especially those with HIV infection, the risk of developing TB disease is considerably higher than for persons with normal immune systems.

There is no gold standard test for LTBI. Indeed, the low tissue bacterial burden associated with LTBI works against any diagnostic strategy focused on the identification of the bacteria or its components. The diagnosis of LTBI is rather indirect and relies on evidence of a cellular immune response to mycobacterial antigens. The most commonly used tests for LTBI diagnosis are the intradermal tuberculin test (TST) and IGRA. Persons who have received BCG (either as a vaccine or for cancer therapy) and persons from groups that historically have poor rates of return for TST reading, are preferred for IGRAs testing.

Wantai’s TB-IGRAs (Interferon Gamma Release Assay) are intended for use as an aid in the diagnosis of TB infection including both latent Tuberculosis infection and Tuberculosis disease.