Which individuals should be screened for latent tuberculosis infection?

Which Patients to Screen for Latent TB?

Screen individuals at increased risk for TB infection or progression to active disease—not the general population—because targeted testing identifies those who will benefit from treatment while avoiding unnecessary testing in low-risk persons where prevalence is ≤1%. 1

High-Priority Populations Requiring Systematic Screening

Mandatory Screening Groups (Strong Recommendations)

These populations have the highest risk for either TB infection or progression to active disease and must be systematically screened:

• People living with HIV – annual reactivation risk 5–10%, with increased risk of meningitis, disseminated disease, or death if active TB develops 1
• Close contacts of persons with active pulmonary TB – highest risk of recent infection and progression within the first 1–2 years 1
• Patients initiating anti-TNF-α antagonists or other biologic therapy – immunosuppression dramatically increases reactivation risk 1
• Patients receiving chronic dialysis – increased progression risk due to uremia-associated immunosuppression 1
• Candidates for organ or hematologic transplantation – pre-transplant immunosuppression and post-transplant medications increase risk 1
• Persons with silicosis – 30-fold increased risk of progression to active TB 1
• Infants and children aged <5 years exposed to adults with TB – increased risk of disseminated disease, meningitis, and death 1

High-Priority Groups for Consideration (Conditional Recommendations)

Screen these populations when resources permit, as they have elevated but somewhat lower risk:

• Prisoners and residents of correctional facilities – congregate settings with high TB prevalence 1
• Healthcare workers serving high-risk populations – occupational exposure risk 1
• Recent immigrants from high TB burden countries (Africa, Asia, Eastern Europe, Latin America, Russia) – rates approach country of origin for first several years after arrival 1
• Homeless persons – congregate shelter settings and social determinants increase risk 1
• Illicit drug users – increased infection risk and progression risk 1
• Residents and employees of long-term care facilities and homeless shelters – congregate settings with vulnerable populations 1

Additional Medical Risk Factors for Progression

Screen patients with these conditions who also have other risk factors for infection:

• Recently infected persons (within past 2 years) – 12.9 cases per 1,000 person-years in first year versus 1.6 per 1,000 in subsequent years 1
• Persons receiving immunosuppressive therapy: systemic corticosteroids ≥15 mg prednisone daily, post-transplant immunosuppression 1
• History of untreated or inadequately treated TB, including fibrotic changes on chest X-ray 1
• Chronic renal failure, leukemia, lymphoma, cancer of head/neck/lung 1
• Diabetes mellitus – but only if other risk factors present 1
• Gastrectomy or jejunoileal bypass 1
• Body weight <90% ideal 1
• Cigarette smokers – but only if other risk factors present 1

Populations NOT Requiring Routine Screening

Do not screen the following groups unless they meet other high-risk criteria, as systematic testing is not cost-effective:

• Persons with diabetes alone (without other risk factors) 1
• Persons with harmful alcohol use alone 1
• Tobacco smokers alone 1
• Underweight persons alone 1
• General U.S. population with no risk factors (prevalence ≤1%) 1
• Administrative screening (e.g., school teacher certification) 1

Critical Screening Principles

Targeted Testing Philosophy

• Screen only if you intend to treat – testing should be limited to persons who would benefit from treatment if LTBI is detected 1, 2
• Risk stratification is essential – categorize patients by risk for infection (Box 1 criteria) and risk for progression (Box 2 criteria) 1
• Replace widespread screening with targeted testing – focus resources on highest-risk groups rather than low-yield populations 1

Pre-Screening Requirements

Before testing for LTBI, systematically screen for symptoms of active TB:

• Ask about cough >2–3 weeks, hemoptysis, fever, night sweats, weight loss, chest pain, dyspnea, and fatigue 1, 3
• Any TB symptom mandates investigation for active disease before proceeding with LTBI testing 1, 3
• Obtain chest radiography if symptoms present or if active case-finding is intended 1

Test Selection

• IGRA preferred over TST in BCG-vaccinated individuals – superior specificity without BCG cross-reactivity 1, 3, 4, 5, 6
• Either TST or IGRA acceptable in non-BCG-vaccinated persons in high-income countries with TB incidence <100 per 100,000 1, 4
• TST preferred in children <5 years 3
• Dual testing (TST + IGRA) may be considered in high-risk situations before immunosuppressive therapy; positive result on either test is considered positive 3

Common Pitfalls to Avoid

• Never screen low-risk populations – prevalence ≤1% makes testing inefficient and increases false positives 1
• Never test without intent to treat – positive results obligate treatment consideration, so only test those who would benefit 1, 2
• Never skip symptom screening – testing symptomatic patients for LTBI risks missing active TB and creating monotherapy-induced resistance 1, 3
• Never use TST alone in BCG-vaccinated persons – high false-positive rate undermines screening efficiency 1, 3, 4, 5
• Never assume diabetes, alcohol use, or smoking alone warrant screening – these require additional risk factors to justify testing 1