Their developer Ralph Weissleder, from Harvard Medical School, points out that the diagnosis of TB generally takes about two weeks because the bacteria is first spotted in sputum under a microscope, and then the suspect samples are sent away for confirmation.
That leads to a delay in treatment, and risks continued spread of the disease, points out the researcher.
Weissleder says that the new test gives the answer in half an hour.
A paper describing this test, published in the journal Angewandte Chemie, says that doctors can simply add the sputum to a solution containing nanoparticles with an iron core encased in iron oxide.
The report further says that each nanoparticle is loaded with antibodies that encourage any TB-causing bacteria in the sputum to bind to it
According to New Scientist magazine, the solution is fed through a lab-on-a-chip which blocks and concentrates the nanoparticles that have bacteria attached to them but lets the other nanoparticles through.
A small magnetic scanner encircling the chip then registers the presence of bacteria-laden nanoparticles.