Prior research has indicated that healthcare personnel (HCP) who work in areas where Mycobacterium tuberculosis poses an occupational hazard are at high risk of tuberculin skin test (TST) positivity and subsequent conversion to active tuberculosis (TB). U.S. medical laboratory microbiologists confront similar hazards but have not been studied outside of the HCP aggregate. The purpose of this study was to fill this gap by examining the relationships between the predictor variables of self-reported history of bacille Calmette-Guerin (BCG) immunization, place of birth, and years of laboratory experience and the outcomes of self-reported lifetime TST positivity, preventive treatment noninitiation, and barriers to treatment adherence for this subgroup. This quantitative, cross-sectional study was guided by the epidemiologic triad model. A researcher-designed self-administered questionnaire including Part A of the Brief Medication Questionnaire was mailed to 4,335 U.S. microbiologist members of the American Society for Clinical Pathology. From the 1,628 eligible respondents, results showed that prevalence of positive TSTs (17.0%) and treatment noninitiation (9.8%) was low. Multivariate analysis identified BCG and foreign birth, as well as age, nonoccupational exposure, history of TB, work in mycobacteriology, and work outside of microbiology as predictors of a positive TST; foreign birth was a predictor of treatment noninitiation. Additional research is needed to identify other laboratorian groups at increased risk for developing TB. These results enhance positive social change by helping to inform recommendations in the global fight to stop the spread of TB, as well as improve allocation of resources among this specific group of HCP.