Latent Tuberculosis Infection Test Agreement in the National Health and Nutrition Examination Survey

Abstract

Rationale: Latent tuberculosis infection (LTBI) test discordance is poorly understood.Objectives: To determine the frequency and predictors of tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube test (QFT) discordance in the U.S. population. Methods:We analyzed data from a representative sample of the U.S. population ages 6 years and older who participated in the 2011-2012 National Health and Nutrition Examination Survey. We determined prevalence estimates of test positivity, calculated test agreement and kappa statistics, and performed multivariable logistic regression to determine predictors of discordance.Measurements and Main Results: LTBI prevalence among the U.S. born ranged from 0.6% to 2.8%, depending on how LTBI was defined, with test agreement 97.0% and kappa 0.27 (95% confidence interval, 0.18-0.36). Prevalence among the foreign born ranged from 9.1% to 20.3%, depending on how LTBI was defined, with test agreement 81.6% and kappa 0.38 (95% confidence interval, 0.33-0.44). TST 1 /QFT 2 discordance was associated with age, male sex, black race, Mexican-American ethnicity, previous TB exposure, and past LTBI treatment in U.S.-born participants, but only with higher lymphocyte count in foreign-born participants. TST 2 /QFT 1 discordance was associated with older age, previous TB exposure, and past LTBI treatment in U.S.-born participants and with older age, male sex, and past LTBI treatment in foreign-born participants. Conclusions:In the largest population-based sample of concurrently performed TST and QFT tests in a low tuberculosis incidence population, prevalence estimates depended heavily on how LTBI was defined and test agreement was only fair. We identified several predictors of discordance warranting further study.

Long-term Stability of Resistance to Latent Mycobacterium tuberculosis Infection in Highly Exposed Tuberculosis Household Contacts in Kampala, Uganda

“…Abbreviations: BAFF, B-cell activating factor; IFN, interferon; IL1, interleukin-1; LTBI, latent M.tb infection; MCSF, macrophage colony stimulating factor 1; MIP1, macrophage inflammatory protein 1-alpha; RSTR, resister phenotype; SD, standard deviation; TNFR, tumor necrosis factor receptor superfamily member 3. exposure to both TB and HIV [5]. Second, use of both the TST and QFT is important in order to avoid misclassification from assay discordance [27,28]. Third, longitudinal sampling (with both TST and QFT) is critical to identify TST/QFT conversion events.…”

<p>Association between vitamin D and latent tuberculosis infection in the United States: NHANES, 2011–2012</p>

“…Responses coded as “don’t know”, “refused”, or “missing” in the original NHANES data were treated as missing. We accounted for the complex multi-stage stratified sampling technique of the NHANES by using Medical Examination Center sample 2-year weights to adjust for unequal probability of selection and nonresponse; additional weights were calculated for TST or QFT-GIT nonparticipation 28. For descriptive statistics, weighted numbers and percentages for categorical variables were used.…”

Performance of the QuantiFERON®-TB Gold In-Tube assay in tuberculin skin test converters: a prospective cohort study

“…While the operating characteristics of IGRAs have been compared against the TST in numerous cross-sectional and prevalence studies, 10–13 their performance has not been compared fully in incidence cohorts among TST converters, especially in adults from low- and middle-income countries. In only one study from South Africa, a commercial IGRA—the QuantiFERON ® -TB Gold In-Tube test (QFT-GIT; Qiagen, Hilden, Germany)—was evaluated in adolescents who experienced TST conversion, and the concordance between the two tests was excellent.…”