What defines a false-positive result?
A false-positive TST or QFTG result is one that is interpreted as positive for a particular purpose (i.e., infectioncontrol surveillance versus medical and diagnostic evaluation) in a person who is actually not infected with M. tuberculosis. False-positive TST results are more likely to occur in persons who have been vaccinated with BCG or who are infected with NTM, also known as mycobacteria other than TB (MOTT). A false-positive TST result might also be caused by incorrect reading of the TST result (reading erythema rather than induration) or use of incorrect antigen (e.g., tetanus toxoid). • Is placing a TST on a nursing mother safe? Yes, placing a TST on a nursing mother is safe. • A pregnant HCW in a setting is reluctant to get a TST. Should she be encouraged to have the test administered? Yes, placing a TST on a pregnant woman is safe. The HCW should be encouraged to have a TST or offered BAMT. The HCW should receive education that 1) pregnancy is not contraindication to having a
