New TB blood test as good as old skin test

BERKELEY, Calif., Jun 07, 2005 (United Press International via COMTEX) -- A recent study has determined blood-based tuberculosis testing is equally as accurate as the old skin test.

The results of the study by researchers from the University of California at Berkeley, and the Mahatma Gandhi Institute of Medical Sciences in India mean switching to the more expensive blood test may not be necessary for people in developing nations.

Dr. Madhukar Pai at UC Berkeley's School of Public Health and lead author of the study said the tuberculin skin test, in which one's skin is pricked with antigens from Mycobacterium tuberculosis, had stood alone for more than 100 years as the method for detecting latent TB.

However, the skin test requires the patient to return three days later so health workers can measure the resulting skin bump.

The more advanced blood assay requires only one visit by the patient, and its results don't rely upon the subjective interpretation of a health worker. However, the new test requires special lab facilities, making it more expensive than the old skin test.

The results of the study appear in a special June 8 theme issue on tuberculosis in the Journal of the American Medical Association,