Health Update: An improved test for TB

A MORE accurate test to detect tuberculosis, which causes three million deaths a year, may soon replace the skin test developed more than 50 years ago, says a report in New Scientist. Incidence of the disease is thought to be rising as a result of the spread of HIV. Researchers at the TB unit of the Medical Research Council, based at Hammersmith Hospital, London, say the new test will lead to earlier detection.

The old test involves injecting the skin with protein segments from the TB bacterium. In people suspected of infection, this produces a red swelling at the injection site, but the test does not always distinguish genuine infection from the BCG vaccination or the presence of harmless micro-organisms. Scientists are developing a test that can verify the presence of active disease.