A 6-kDa early secreted antigenic target (ESAT-6) blood test that is more sensitive could lead to the reduced spread of tuberculosis (TB), according to a news release from the Association for Diagnostics & Laboratory Medicine (ADLM). The research that led to this revelation was presented at the ADLM 2026 meeting.

The scientists utilized a new biosensor to detect ESAT-6 in more than 200 patients. The marker successfully differentiated between patients with TB and patients without TB. Additionally, the researchers noted a stepwise increase in the blood concentration of the marker across the spectrum of TB infection, with the lowest levels in uninfected people with TB contacts, medium amounts in those with latent TB, and the highest levels in patients with active TB. This strong, independent association held true even after the researchers accounted for other factors that could impact patients’ TB status, such as age, sex, and the presence of diabetes.  

Unlike biomarkers that measure the body’s immune response to infection, ESAT-6 is derived directly from the TB bacteria. The study found ESAT-6 did a better job discriminating among TB patient groups than two common blood-based markers.  

Because the study used a design in which patients’ disease status was known from the outset, further research is needed to confirm that ESAT-6 can predict TB status in real time.

Although sputum cultures remain essential for verifying TB and providing information about drug resistance, ESAT-6 holds promise as a practical tool for triaging patients in instances when sputum-based diagnostics are limited or delayed.