However, at the rise of the millennium, new blood assays (QuantiFERON-TB, CSL Limited), which measure gamma interferon production when M. tuberculosis-specific proteins, such as the ESAT-6, are incubated with venous blood samples, are promising for the recognition of infection with Mycobacterium tuberculosis, since they are not influenced by past BCG exposure [45]. Here, IFNG is linked to infection.