Screening for Latent Tuberculosis Infection (LTBI) in US Army Recruits

Not Applicable

Completed

Lead Sponsor: Henry M. Jackson Foundation for the Advancement of Military Medicine

Brief Summary: The overall objective of this study is to assess the feasibility and potential impact of using a targeted testing approach and 2 interferon-gamma release assays (IGRA) to screen for latent tuberculosis (TB) infection (LTBI) among military recruits. The current policy of universal application of the Mantoux tuberculin skin test (TST) to screen for LTBI may result in many TST reactions among recruits who are at low risk for LTBI. The central hypothesis is that targeted testing by use of the questionnaire will reduce unnecessary testing of low-risk recruits without affecting the identification of higher-risk recruits. The secondary hypothesis is that many discordant results between the TST and IGRA may be explained by cross-reactivity to non-tuberculous mycobacteria (NTM) with the TST.

Recruitment & Eligibility

Inclusion Criteria

Any recruit, age 18 years or older, undergoing routine entry-level medical processing at Fort Jackson

Exclusion Criteria

If they have history of severe reactions to TST (e.g., blistering, scar, or symptoms of immediate hypersensitivity)
If they are unwilling to provide written consent for the study
If they are unwilling to provide Health Insurance Portability and Accountability Act (HIPAA) authorization

Arm && Interventions

Group	Intervention	Description
All study participants	BST	Subjects administered the TB skin test, Battey skin test, QFT-GIT, and T-Spot
All study participants	T-spot	Subjects administered the TB skin test, Battey skin test, QFT-GIT, and T-Spot
All study participants	TST	Subjects administered the TB skin test, Battey skin test, QFT-GIT, and T-Spot
All study participants	QFT	Subjects administered the TB skin test, Battey skin test, QFT-GIT, and T-Spot

Primary Outcome Measures

Name	Time	Method
TST Induration Will be Interpreted Relative to Risk, in Accordance With Published CDC Guidelines.	48-72 hrs post administration	Risk stratification and test result. Risk was stratified by the use of risk factors identified by questionnaire according to the 5, 10 and 15 mm criteria (CDC Morbidity and Mortality Weekly Report Recommendations and Reports 2000. Targeted Testing for Latent Tuberculosis Infection.) The number of 1803 is used here because that is the number for which valid results were available for all 4 tests. The number presented in each category is the number of participants that had positive results. We are only presented a risk stratified interpretation for the TST (not the QFT, T-spot, and BST) because that is the only test for which this methodology is accepted in scientific and medical use. It is also the only test for which we had pre-specified the use of this methodology in the protocol.

Secondary Outcome Measures

Name	Time	Method
Positive QFT-GIT Result	48-72 hours after enrollment	The number of subjects is 1781 (less than the original 1978) because we analyzed only those who had valid results by all 4 tests to have a fair comparison. Additionally, we excluded those subject who had a borderline T-Spot result, as we were not able to make valid comparisons with these results.