Latent Tuberculosis Infection Detection

Latent tuberculosis infection (LTBI) detection identifies people infected with Mycobacterium tuberculosis who do not have symptoms or clinical evidence of active tuberculosis. Detection supports preventive treatment, outbreak control, and progress toward global tuberculosis elimination. The principal tools are tuberculin skin testing (TST) and interferon-gamma release assays (IGRAs), interpreted alongside exposure history, epidemiology, medical risk factors, and evaluation for active disease. A positive test indicates immune sensitization rather than proof of active tuberculosis, so chest imaging and clinical assessment remain essential.

The policy direction is increasingly toward targeted testing of people at elevated risk rather than indiscriminate population screening. Priority groups commonly include close contacts of infectious cases, people living with HIV, patients receiving immunosuppressive therapies, children exposed to tuberculosis, recent arrivals from countries with higher tuberculosis incidence, and workers or residents in congregate settings. IGRA use is expanding where prior Bacille Calmette–Guérin vaccination can reduce TST specificity, while TST remains valuable where laboratory infrastructure is limited. Persistent implementation challenges include missed follow-up, test variability, limited access to confirmatory assessment, and incomplete linkage from a positive result to preventive therapy.

Artificial intelligence is most immediately relevant to LTBI detection as a support layer rather than a replacement for microbiological, immunological, or clinical judgment. Validated algorithms can assist with chest-radiograph triage for possible active tuberculosis, identify people needing additional evaluation, flag inconsistent records, and help prioritize outreach after testing. Machine-learning tools may also improve workflow management in high-volume programs by predicting missed appointments or identifying incomplete treatment pathways. However, AI performance can vary by population, imaging equipment, disease prevalence, and data quality. Safe deployment requires external validation, transparent thresholds, privacy safeguards, human oversight, and monitoring for unequal performance across demographic and geographic groups.

North America generally combines established laboratory capacity with targeted testing policies focused on contacts, immunosuppressed patients, healthcare personnel, and populations with recent exposure or migration links. Latin America faces continued variation in access, with opportunities to integrate LTBI services into primary care, HIV programs, and contact investigation. Europe benefits from coordinated guidance and strong laboratory networks, while differences in migration patterns, national screening policies, and TST or IGRA availability influence implementation. The Middle East requires adaptable approaches for displaced populations, congregate settings, and cross-border mobility. Africa’s priorities include integrating LTBI detection with HIV and tuberculosis services while addressing laboratory, workforce, and follow-up constraints. Asia-Pacific contains diverse high-burden and low-burden settings, making locally calibrated contact investigation, occupational screening, and preventive treatment pathways especially important.

ASEAN countries can benefit from interoperable approaches to cross-border contact investigation, migrant health, and integration with primary-care services. BRICS members face varied tuberculosis burdens and health-system capacities, creating a need for scalable protocols that preserve diagnostic quality while expanding access. The European Union can strengthen consistency through shared evidence standards, laboratory quality assurance, and coordinated approaches for mobile and migrant populations. G7 systems generally have advanced diagnostic infrastructure but must maintain targeted screening, equitable access, and reliable follow-up in underserved communities. GCC countries require approaches suited to substantial migrant-worker populations, occupational settings, and cross-border movement. NATO members may prioritize standardized screening and referral procedures for military personnel, deployed populations, and other high-mobility groups while preserving national clinical governance.

Australia emphasizes targeted screening for people with exposure, migration, or clinical risk factors within strong public-health systems. Brazil and India require integration with tuberculosis-control and primary-care services, particularly for contacts and people living with HIV. Canada, France, Germany, Italy, Spain, the United Kingdom, and the United States generally rely on risk-based strategies supported by public-health contact investigation, with national differences in preferred tests and guidance. China, Japan, and South Korea combine substantial technical capacity with the need to tailor screening to older adults, healthcare personnel, contacts, and other defined risk groups. Mexico and Russia must align detection with regional epidemiology, contact tracing, laboratory access, and continuity of preventive treatment. Across all listed countries, a positive LTBI test should trigger structured assessment for active disease and a documented preventive-treatment decision rather than stand-alone testing.

Industry and public-health leaders should define testing eligibility using transparent risk criteria, select TST or IGRA according to population needs and operational capacity, and establish clear pathways for ruling out active tuberculosis. Quality programs should include specimen and laboratory controls, staff training, standardized interpretation, and mechanisms to manage indeterminate or borderline results. Services should measure the complete cascade from invitation and test completion through clinical evaluation, preventive-treatment initiation, and adherence support. Digital tools can improve reminders, referral tracking, and reporting, but they should be governed for privacy, explainability, and equity. Procurement and implementation decisions should favor interoperable systems, dependable supply, local validation, and partnerships with community organizations serving mobile or underserved populations.

This executive summary is based on established public-health principles and clinical guidance concerning LTBI testing, tuberculosis epidemiology, preventive treatment, diagnostic implementation, and responsible use of artificial intelligence. The synthesis distinguishes infection detection from active-disease diagnosis and avoids treating a test result as a definitive clinical conclusion. Regional, group, and country observations are framed around documented differences in epidemiology, health-system capacity, mobility, screening policy, and laboratory access. Interpretation should be updated against current national guidelines, regulatory requirements, peer-reviewed validation studies, surveillance reports, and program-level cascade data before operational decisions are made.

LTBI detection is most effective when targeted to people with meaningful risk, performed with an appropriately selected test, and connected immediately to evaluation for active tuberculosis and preventive-treatment decisions. The central opportunity is not testing in isolation but improving the complete care pathway, including access, quality assurance, follow-up, and adherence support. Regional and national differences make adaptable implementation essential. Artificial intelligence can reinforce triage and program management when independently validated and carefully governed, while clinical expertise and public-health accountability remain indispensable.