micheljd

For anyone who has had a TST (TB skin test), I am curious what advantages a TST test has over an IGRA (TB blood test). It seems like, in general, TB skin tests are more painful than a blood draw (although many people don't experience too much pain). A person needs two skin injections (for a 2-step test), as opposed to one blood draw. There are also more side effects for a TB skin test, such as blistering, itchiness, and a risk for allergic reaction (many places require epinephrine available just in case). Although those side effects doesn't happen to everyone, it seems much more likely than a side effect to a blood draw. The IGRA is generally more accurate than TB skin testing, and the test can be completed in one visit, instead of four. Many studies have shown IGRAs to be more cost-effective long-term for employers. I know many people don't find two skin tests to be a big deal, but I am interested in why a person would choose two skin tests over one blood draw. The CDC has stated the two are always interchangeable, and I am not aware of any place that only accepts skin tests (even if they don't mention the other options). If an employer or health insurance is paying, why do people choose a 2-step skin test?