Replacing the tuberculin skin test with a specific blood test

For almost 100 years has the tuberculin skin test (TST) been used for the support the diagnosis of active and latent TB infection. The TST test has, however, a number of limitations most notable low specificity in BCG vaccinated individuals due to cross-reactive components in PPD and the M. bovis BCG vaccine strain and an intensive search for new and more specific diagnostic antigens has therefore be ongoing. In this review we describe the discovery process leading to the identification of the M. tuberculosis specific antigens ESAT6 and CFP10; two low molecular weight proteins which are highly sensitive and specific for detection of a M. tuberculosis infection.