Figure 1.

IGRA tests, results, and associated treatment among children younger than 2 years of age. There were no borderline T-SPOT results.

¹A total of 10 tests were repeated among 9 patients. Three negative repeat tests followed an initial invalid IGRA. Two negative repeat IGRAs followed an initial positive IGRA. Four negative repeat tests followed initial negative IGRAs. The one indeterminate repeat test followed an initial negative IGRA result.

² Two patients with positive IGRA results did not receive treatment. One patient had received a bone marrow transplant and it was suspected that the donor T cells were sensitized resulting in positive IGRA. The other patient was diagnosed with a primary immunodeficiency with initial positive T-SPOT and two subsequent negative T-SPOT tests. The first positive T-SPOT was thought to be a false positive result.

³ Window prophylaxis was defined as treatment for TB infection for close contact exposure despite negative TB testing.