The present invention describes compositions for both diagnostic and therapeutic applications. In one embodiment, the present invention contemplates a method of identifying an active M. tuberculosis infection. In another embodiment, the present invention contemplates a method of monitoring a M. tuberculosis infection. In yet another embodiment, the present invention contemplates a method of monitoring a patients response to treatment for an active M. tuberculosis infection. In a further embodiment, the present invention contemplates a method of monitoring a patients response to treatment for an active M. tuberculosis infection.