TB affects millions in the developing world

TDR/Image: 0313699

Tests for tuberculosis (TB) that are used on millions of people each year in developing countries do not work and may be worsening the epidemic in some high-burden countries, according to the WHO.

Widespread use of the serological tests, which aim to detect antibodies in blood serum, is leading to misdiagnosis and wasted resources, according to a report released last month by the WHO Strategic and Technical Advisory Group for TB and covered by an article in The Lancet.

The tests are available commercially and are employed on 1.5 million people with suspected TB in India alone.

The WHO will soon release a 'negative policy recommendation' advising against use of the tests, some of which are laboratory-based while others are rapid dipstick tests. None is good enough to replace the gold standard of sputum microscopy, says the expert group.

Such tests, if they worked, could fulfil an overwhelming need for point-of-care diagnosis, according to Madhukar Pai, co-chair of the Stop TB Partnership's new diagnostics working group.

"The pity is that they don't work. In fact they're inaccurate and useless," he told The Lancet.

Link to the WHO report [300kB]