Recent study has shown a better way to diagnose tuberculosis (TB). Traditional methods to test TB sometimes result in showing wrong people in need of treatment of TB whereas people with TB infection are diagnosed healthy. Researchers claim that that new blood test will equip doctors to more accurately pinpoint patients likely to develop the symptoms of tuberculosis.

Traditional testing method involves injecting the subject with components of the TB bacterium; a resultant swelling of the skin can signal dormant tuberculosis.  

The new method detects a chemical secreted by a type of lymphocytes (T-cells) in response to a protein not found in the BCG vaccine and most environmental Mycobacteria. The test results are therefore not confounded by previous BCG vaccination, conferring higher specificity than the tuberculin skin test. Moreover, results are available the next day.

Recent study focused on 908 healthy children in Turkey exposed to tuberculosis in their homes. Both traditional method and new way were used to test TB in the children. The skin test showed that 580 children required drugs to ward off active TB, but the blood test pointed to just 380. Twelve children developed active TB even with treatment. Ajit Lalvani, a researcher at Imperial College London said that this research suggests that ELISpot is 1.5 times better at spotting tuberculosis carriers than the skin test.