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.
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.