<i>Notes from the Field:</i> Maximizing Tuberculosis Testing After a School-Based Exposure — Lake County, Illinois, 2025

On March 18, 2025, a case of pulmonary tuberculosis (TB) was reported to the Lake County Health Department and Community Health Center (LCHD) in Illinois.The patient had been present at a Lake County school from November 6, 2024, through March 17, 2025, while infectious.In consultation with the school, LCHD organized testing to identify TB cases and prevent progression of latent TB infection (LTBI) for exposed persons.Among 155 school contacts, LCHD examined 143 (92%), including 128 persons who completed two rounds of testing (including one case of LTBI diagnosed during the second event), eight who were tested for the first time during the second event, and seven who received a diagnosis of LTBI during the first testing event.The school's awareness of community challenges, including low health literacy and mistrust of government institutions, helped guide LCHD's response.This activity was reviewed by the Illinois Department of Public Health and was considered a public health practice activity conducted consistent with applicable state law*; institutional review board review was not required.