A new study presented at ADLM 2026 in Anaheim, California, found that a simple blood test could accurately identify tuberculosis among patients with varying degrees of exposure to the disease, according to findings released on July 28. Researchers said that if confirmed, these results could help save millions of lives and address a global health emergency.
The World Health Organization estimates that a quarter of the global population has been infected with Mycobacterium tuberculosis, the bacteria causing TB, and that five to ten percent will develop active disease. TB is almost always curable with antibiotic therapy when detected in its initial stages. Traditionally, diagnosis relies on assessing sputum samples from patients’ lungs and airways.
Dr. Pan said not all patients can produce sputum when they first seek medical care, especially those with early disease or low bacterial burden. “For that reason, non-sputum-based diagnostic tools are urgently needed,” Dr. Pan said.
The researchers evaluated a blood marker produced by the bacteria called 6-kDa early secreted antigenic target (ESAT-6). While ESAT-6 has been studied before, most sensors used to detect it have not been sensitive enough to distinguish active pulmonary TB from latent infection or other lung diseases. Dr. Pan’s team used a new biosensor designed to overcome this limitation. “The novelty of our study lies in the highly sensitive quantification of circulating ESAT-6,” Dr. Pan said.
In their analysis of blood samples from 217 participants—both those with active pulmonary TB and controls—the ESAT-6 marker differentiated between TB and non-TB patients effectively. The researchers observed a stepwise increase in ESAT-6 levels across different stages: lowest in uninfected people exposed to TB contacts; medium amounts in those with latent infection; highest in patients with active TB. This association remained after accounting for factors such as age, sex, and diabetes status.
Unlike biomarkers measuring immune response to infection, ESAT-6 is derived directly from the bacteria itself—a feature Dr. Pan said may explain its strong performance identifying active cases: “We believe this is one reason why it performs so well in identifying active TB.” The study also found ESAT-6 outperformed two common blood-based markers for distinguishing patient groups.
Researchers cautioned that further research is necessary since patient disease status was known during testing: “We are currently planning a prospective study to further evaluate if this can be used in a real-world clinical setting,” Dr. Pan said.
While sputum cultures remain essential for confirming diagnosis and providing drug resistance information, researchers say ESAT-6 holds promise as an additional tool for triaging patients when sputum-based diagnostics are limited or delayed.
