New blood test can predict TB onset up to two years before signs

A new blood test published in the American Journal of Respiratory and Critical Care Medicine claims the ability to predict TB’s onset up to two years prior to its development in people living with active TB.

While other tests currently exist that track TB progression, professor Gerhard Walzl, lead study author, said that this new test gives positive results for a smaller percentage of high-risk household members than those existing tests. Current tests require putting large numbers of low-risk people through ultimately unnecessary preventative treatments, despite the fact that only 5-20 percent of those infected with TB actually develop it.

“We found that this prediction [up to two years before the onset of the disease] is possible through measurements of a combination of a four-gene signature in the blood,” Walzl said. “This signature, known as ‘RISK4,’ was found to be present in all cohorts in the study, from South Africa, Gambia and Ethiopia.”

The genes tracked are associated with inflammatory responses. The research focused on 4,466 healthy participants from 1,098 households where active TB thrives.

“The individual components of this signature may not be sufficient to deliver an accurate diagnosis of prediction, but a combination of these markers improves its accuracy,” Walzl said.

Given that numerous companies possess the ability to measure and assess the four involved genes at present, Walzl noted that primary health clinics could hopefully use the tests.