Characteristics of TB cases without documented sputum culture in the United States, 2011-2021

BACKGROUND: Culture -based diagnostics are the gold standard for diagnosing pulmonary TB (PTB). We characterized culture practices by comparing cases with documented sputum culture to those without. METHODS: Using multivariable logistic regression, we examined associations between PTB case characteristics and no documented sputum culture reported to the U.S. National TB Surveillance System during 2011- 2021. RESULTS: Among 69,538 PTB cases analyzed, no sputum culture attempt was documented for 5,869 (8%). Non -sputum culture specimens were documented for 54%, 80%, and 89% of cases without documented sputum culture attempts among persons aged <15 years, 15-64, and 65þ years, respectively; bronchial fluid and lung tissue were common non -sputum specimens among cases in persons .15 years old. Having no documented sputum culture was associated with age <15 years (aOR 23.84, 99% CI 20.09-28.27) or >= 65 years (aOR 1.22, 99% CI 1.07-1.39), culture of a non -sputum specimen (aOR 6.57, 99% CI 5.93-7.28), residence in a long-term care facility (aOR 1.58, 99% CI 1.23-2.01), and receiving TB care outside of a health department (aOR 1.79, 99% CI 1.61-1.98). CONCLUSIONS: Inability to obtain sputum from children and higher diagnostic suspicion for disease processes that require tissue -based diagnostics could explain these findings.