Distribution of immunodiagnostic test results.

<p>TST: tuberculin skin test; ELISpot: enzyme-linked immunospot. ^Δ In these 17 cases a skin test could not be performed. Because we did not obtain their informed consent for participation, these individuals were not tested with ELISpot in the study but tested by the city's health authorities with ELISA (<i>QuantiFERON-TB Gold</i>). $ These 2 contacts did not receive IL-2 ELISpot testing because they had only agreed on testing with test methods already approved by the health authorities. We performed IFN-γ ELISpot here. <i>§</i> In this case the amount of blood taken from the student was not sufficient to perform both ELISpot tests. This contact later received ELISA testing from the city's health authorities, in which she showed a negative result. <i>*</i> These 3 contacts or their parents did not agree on IL-2 ELISpot testing but only on test methods already approved by the health authorities. <i>^#</i> These 4 contacts showed an indeterminate IFN-γ ELISpot result. Because skin testing could not be performed, the city's health authorities then tested these 4 with ELISA, in which all of them showed a negative result.