Clinical evaluation for diagnosing active TB disease and transitional change of two commercial blood tests

This is the authors' abstract. We don't add key points for this paper.

We compared the usefulness of TST, QFT-TB and T-SPOT.TB for the identification of patients with active tuberculosis (TB) disease and investigated transitional change in both tests during anti-tuberculous treatment. The subjects were 50 healthy volunteers and 48 patients with active TB disease between October 2005 and December 2006. Among active TB disease patients, 60% had a positive TST result, 81% had a positive QFT-TB result, and 87% had a positive T-SPOT.TB result. Indeterminate results of QFT-TB and T-SPOT.TB were recognized in 12% and 6% of patients, respectively. Negative results on QFT-TB and T-SPOT.TB were 6% each. QFT-TB had a sensitivity of 81% for active TB disease. T-SPOT.TB had a sensitivity of 88% for active TB disease. With regard to transitional changes in QFT-TB results and T-SPOT.TB results, both test results showed a positive response in over 40% of patients 12 months after anti-tuberculous treatment. In conclusion, both blood assays seemed to be more useful than TST for the identification of patients with active TB disease. However, neither of the 2 blood tests appears to provide any certainty regarding the cure of infection.