Editorial: Immuno-diagnosis of active tuberculosis; are we making progress?

Active tuberculosis (ATB) diagnosis suffers from several knowledge gaps and challenges, including the need for newer assays with faster turn-around-time (TAT), high sensitivity and specificity, lower costs, and the potential for Point-of-Care (POC) use assays. Towards this goal, we need novel tests that can be used at the population level to screen and/or test high risk populations, including household contacts of sputum positive index patients and persons living with HIV/AIDS. In addition, tests that can be adaptable towards use in treatment follow-up (to predict cure or relapse/reinfection), and as potential surrogate markers of tuberculosis (TB) vaccination are important towards the global control of tuberculosis. A test using blood-based samples would have potential for future studies to “estimate” the mycobacterial load in the body (akin to the HIV viral load test), which would improve the treatment of ATB, and latent tuberculosis infection (LTBI). In addition, immune-based POC tests for ATB diagnosis have the potential for low invasiveness, being user friendly for staff and patients, minimal training needs, greater simplicity, and low cost; making immuno-diagnosis of active tuberculosis a promising approach. To date, a number of studies have been done in both high and low TB endemic settings to diagnose, or even predict, the evolution towards ATB. Much as some studies have shown high sensitivity and specificity (over 85%), there are still many challenges towards the ideal test, and more research needs to be done.