‘One-pot’ test diagnoses TB in an hour

An impediment to effective tuberculosis (TB) treatment is timely diagnosis. In a recent study, researchers developed a “one-pot” test that uses the Nobel Prize–winning gene-editing platform CRISPR to reliably diagnose TB in under an hour. Instead of relying on sputum, the test can be used on a mouth swab and administered without needing trained technicians and laboratory facilities (Nat. Commun. 2025, DOI: 10.1038/s41467-025-63094-x).

TB is estimated to be the world’s leading cause of death from a single infection. In 2023, almost 11 million people had the disease, two-thirds of them in eight countries in Asia and Africa. A current diagnosis gap, which particularly affects these regions, leads to over a third of new cases going undiagnosed every year.

This diagnosis gap is partly because of lack of access and resources. In addition, the conventional way of detecting TB uses sputum (mucous from the lungs), which is difficult to obtain and process. More recently, tongue-swab tests have been emerging as a minimally invasive option for diagnostics.

The new study uses a CRISPR-based assay to detect infection, even in samples with low levels of the tuberculosis bacteria, including stool, spinal fluid, and tongue swabs. Called ActCRISPR-TB, the test is an upgrade of one developed by the researchers in 2022.

CRISPR systems use guide RNA to recognize specific DNA sequences in foreign cells. ActCRISPR-TB uses this mechanism to amplify and detect genetic signals from the DNA of Mycobacterium tuberculosis, the bacteria responsible for TB.

“The first generation of our CRISPR-based assay had a two-step workflow,” says Tulane University’s Zhen Huang, the study’s lead author. “It was not suitable for clinical use. To overcome this, we had to combine the two steps together.”

The test can even be self-administered. “It’s very easy [to use],” Huang says. “Just add your samples into the tube, incubate, and get a result.” The tube contains the reagent and a test strip, and the bands on the test strip indicate the presence or absence of infection within an hour. In case of high bacterial load, a positive result can be detected in 15 min. Even asymptomatic patients shed bacteria, and Huang says this method has the potential to test those cases as well.

“Current testing is still mainly focused on sputum samples,” Huang says. “But a lot of people cannot get detectable sputum samples, including HIV patients and children.” M. tuberculosis also grows very slowly, and it may take 4–8 weeks for a diagnosis using bacterial cultures, he adds. Thus, ActCRISPR-TB could be a promising option for on-site testing to screen TB in communities, especially those in remote or resource-limited settings.

Bhushan Toley, a researcher in point-of-care diagnostics at the Indian Institute of Science who was not part of this study, calls ActCRISPR-TB a “big development” that has the potential to become a quick and easy TB testing solution. Toley says its strongest features are that it uses “minimal instrumentation, and demonstrates the highest sensitivity for TB detection from tongue swabs ever reported.” But he says he would like to see the test further simplified for point-of-care use.

Huang agrees that the test is still too complex for community-wide diagnosis, which is the team’s ultimate goal. The researchers are looking to improve the test, including validating the findings in larger and more diverse groups, testing subclinical cases, and optimizing and standardizing the testing protocol.