The UN health agency said it will issue an unprecedented recommendation against using such tests for the infectious lung disease that affects some 14 million people worldwide. As much as a third of the world's population is thought to harbor the bacteria that causes TB.

"The tests are not reliable and a waste of money and time, putting proper care at risk," said Mario Raviglione, the director of WHO's Stop TB department. A review of the tests has shown that they produce too many false negative and false positive, according to WHO.

Raviglione said that the blood tests "are in fact dangerous to patients, since some cases will not be detected and some will be called TB when in fact they do not have it."