New skin test improves tuberculosis diagnosis in children and adolescents

Tuberculosis (TB) remains a leading cause of illness and death among children worldwide, with nearly 1.3 million cases estimated in 2023 and more than half going undiagnosed. Current diagnostic tools, such as the traditional tuberculin skin test (TST), are limited in accuracy due to interference from Bacillus Calmette-Guérin (BCG) vaccination and non-tuberculous mycobacterial infections. This has created a pressing need for more reliable, child-appropriate methods of TB detection.

A new diagnostic tool—the Creation Tuberculin Skin Test (C-TST)—was evaluated in this Phase III clinical trial. The C-TST is based on a recombinant fusion protein combining ESAT6 and CFP10, two Mycobacterium tuberculosis–specific antigens absent in BCG vaccine strains and most environmental mycobacteria. Researchers assessed its diagnostic accuracy compared to TST and the T-SPOT.TB interferon-gamma release assay in children and adolescents under 18 years old.

The study enrolled 96 participants across four hospitals in China, including children with suspected pulmonary TB, extrapulmonary TB, and non-TB pulmonary diseases. Each participant received all three diagnostic tests. Results showed that C-TST achieved a sensitivity of 83% and a specificity of 100%, outperforming both TST (80.9% sensitivity, 98% specificity) and T-SPOT.TB (76.6% sensitivity, 100% specificity). High concordance was also observed between C-TST and the other two methods.

Importantly, no serious adverse events were reported, and side effects were mild, such as localized skin reactions and low-grade fever. These findings confirm that C-TST is both safe and reliable for use in children and adolescents. The study highlights its potential to serve as a superior alternative to the traditional TST, offering an accurate, non-invasive, and practical solution for TB screening in pediatric populations.