1. IGRAs are more convenient,
2. of the available IGRAs QFT-GIT is the easiest to use,
3. TST is more labour intensive and requires a more qualified practitioner,
4. amongst HCWs QFT has gained a higher degree of confidence than the TST,
5. greater confidence in QFT translates to a higher degree of voluntary preventative treatment.
...IGRAs are, in general, more convenient than the TST for subjects and for the HCWs who run the tests. The QFT assays could be even easier than the T-SPOT.TB to be conducted in clinical laboratories because QFT assays use whole blood specimens with no need for the T-cell fractionation and counting steps in the T-SPOT.TB. The ELISA measurements for QFT assays could be performed with existing facilities common to most clinical laboratories. The QFT-GIT, in which reactions occur in the same tubes for blood collection, is currently considered the easiest to use.
...one of the common concerns regarding IGRAs is their cost. In regard to the initial expenditure on reagents, the assays are several times more expensive than TST, especially in the case of the T-SPOT.TB. Quite a few health economic analyses, however, have shown that IGRAs are more cost-effective in the medium term. Unlike IGRAs that are primarily performed in laboratories, TST is administered and read by nurse practitioners, who are compensated more highly than technologists. The improved sensitivity of IGRAs in vulnerable populations can better identify people with LTBI, which is, if progressed to active TB, associated with potentially more expense for treatment.
...A survey in the summer of 2007 showed that nearly none of the HCWs believed that they were at risk of developing TB and 68% believed that BCG accounted for their positive TST results, with only 11% TST+ HCWs agreeing to undertake the chemotherapy. In comparison, 53% of the HCWs who later tested positive for LTBI according to on-site QFT assays agreed to take the medications. This finding suggested that the implementation of IGRAs in lieu of TSTs to identify TB infection in HCWs at the time of employment would increase their acceptance of preventive treatment for LTBI.
