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Researchers Streamline TB Testing to Speed Treatment

FILE - A physician examines an X-ray picture of a tuberculosis patient.

Researchers have developed a two-pronged, streamlined approach to diagnosing tuberculosis aimed at treated patients more promptly.

Diagnosing the fatal lung disease is difficult using conventional means such as a microscope, in which the presence of the TB bacterium is easily missed in sputum samples.

Instead, researchers are using the latest technology to streamline the diagnosis process.

According to the World Health Organization, tuberculosis causes more deaths globally than any other infectious disease.

Nearly 10 million people are diagnosed with TB each year, and the disease kills approximately 1.5 million people, mostly in low- and moderate-income countries. AIDS patients are at high risk of becoming infected with tuberculosis.

Experts believe many people infected with TB aren’t diagnosed until they become ill or die.

“A major area of research interest for us is looking at how we can improve diagnosis to make sure that patients aren’t missed by the system,” said Priya Shete, a TB researcher at the University of California in San Francisco. “And the goal of catching those patients is to ensure not only timely diagnosis, but timely treatment initiation to try to minimize bad tuberculosis outcomes and also to prevent ... further transmission of the disease.”

Trial program

Shete and her colleagues led a trial program at four health centers in Uganda that aimed to catch more tuberculosis cases.

A total of 822 patients suspected of being infected with TB were referred for testing.

Of those, 12 percent were ultimately diagnosed with the disease. Seventy-five percent of that total was diagnosed the same day with fluorescence microscopy, a more sensitive form of testing than is conventionally done.

Sputum samples of the participants who tested negative were sent to a regional laboratory for an even more sensitive analysis using GeneXpert, which identifies DNA sequences specific to TB. Those results showed that two dozen people who originally tested negative for the bacterium were infected.

Same-day treatment was administered to the 98 patients diagnosed in the first round of testing, while antibiotics were administered six days later to a majority of the patients who were determined to have TB using the genetics test. About 20 percent of the infected patients were lost to follow-up.

The bottom line, Shete says, is many more patients were identified using the two-prong approach than with the traditional testing method.

“You know, at the end of the day, it meant that we got 82 percent of patients, by any means, on therapy, and I think [that shows] the feasibility of some of these types of interventions in even remote, rural settings.”

Researchers now plan to repeat the testing system at 20 clinics in Uganda.

Shete says future work will examine whether TB diagnosis and treatment numbers can be improved by reorganizing health centers to include a staff dedicated to fighting tuberculosis.