A new blood test has been invented. It is able to predict the development of tuberculosis up to two years before its onset in people living with a person with active TB.
People living with a person with active TB are most at risk of developing the disease, but only 5 to 20% of them actually get TB. This blood test that predicts the development of the disease avoids unnecessary preventive treatment for those who are not at risk, according to the results of a study published in the medical journal American Journal of Respiratory and Critical Care Medicine.
Focusing on people living with a person with active TB, the research team recruited 4,466 HIV-negative participants and collected blood samples. They developed a blood test that works by measuring the expression levels of the signature of four genes in the blood known as “RISK4”, associated with inflammatory responses.
“We found that this prediction (up to two years before the onset of the disease) is possible through the measurement of a combination of four genes in the blood,” said lead author Gerhard Walzl, professor at University of Stellenbosch in South Africa.
Tuberculosis, caused by infection with Myobacterium tuberculosis (M. tb), is the leading cause of death in the world caused by a single pathogen. More than 10 million new TB cases are diagnosed each year and nearly two million people die from the disease. Globally, an estimated 1.7 billion people are infected.