Latent tuberculosis infection — MSF Tuberculosis — Médecins Sans Frontières 2026

MSFClinical guideline (chapter)Current edition

From Tuberculosis › Chapter 3: Diagnosis and follow-up investigations · Médecins Sans Frontières, Current online edition, 2026

Diagnostic approach to latent TB infection using tuberculin skin test and interferon gamma release assays for clinicians in resource-limited settings.

In one sentenceLTBI diagnosis requires excluding active TB and demonstrating infection via TST or IGRA; testing not mandatory before treatment in child contacts under 5 or HIV-positive individuals.

Issuer: Médecins Sans Frontières
Edition: Current online edition, 2026
Audience: Clinicians and TB programme staff in resource-limited settings
Evidence: Based on WHO 2018 consolidated guidelines
Reviewed: 21 Oct 2026 · GMJ

Read the original on MSF Whole guideline (PDF)

Summary by GMJ Guidelines Desk•Reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD•Record updated 21 Oct 2026•Next check Apr 2027

What this guideline says

GMJ summary

This section of the MSF tuberculosis guideline describes the diagnosis of latent tuberculosis infection (LTBI), which is based on exclusion of active TB and demonstration of infection through testing. The guideline presents two main diagnostic modalities: the tuberculin skin test (TST) and interferon gamma release assays (IGRAs).

Testing is not mandatory before initiating LTBI treatment in children under 5 years who are household contacts of a TB case, or in children and adults with HIV infection. Both TST and IGRA have limitations, including inability to distinguish latent from active TB. TST can yield false positives due to BCG vaccination and false negatives in HIV-infected patients and malnourished children. IGRAs offer advantages over TST by avoiding cross-reaction with BCG vaccine and most environmental mycobacteria, but require more complex laboratory infrastructure.

After ruling out active TB, a positive TST or IGRA is an indication for treatment of LTBI. The guideline references WHO 2018 consolidated guidelines for programmatic management of latent tuberculosis infection.

Key points

For clinicians — doses and thresholds as stated in the guideline

LTBI diagnosis requires exclusion of active TB plus demonstration of infection through TST or IGRA testing
Testing is not mandatory before LTBI treatment in children under 5 years who are household contacts of TB cases
Testing is not mandatory before LTBI treatment in children and adults with HIV infection
TST has limitations: does not distinguish M. tuberculosis from environmental mycobacteria, cannot differentiate latent from active TB, and can be falsely positive after BCG vaccination
TST frequently yields false negatives in HIV-infected patients and malnourished children
IGRAs (QuantiFERON-TB Gold In-Tube and T-SPOT.TB test) do not cross-react with BCG vaccine or most environmental mycobacteria
IGRAs cannot distinguish latent from active TB and require specialised laboratory equipment and trained technicians
A positive TST or IGRA after excluding active TB is an indication for LTBI treatment

From the guideline

Verbatim

“These tests are not mandatory prior to initiating LTBI treatment in: Children under 5 years household contact of a TB case; Children and adults with HIV infection”

— Médecins Sans Frontières, Latent tuberculosis infection — MSF Tuberculosis, Section 3.2 (2026)

Editor’s perspective

Why this matters for Georgia and the region

Prof. Giorgi Pkhakadze, MD, MPH, PhD

Editor-in-Chief, Georgian Medical Journal · Chair, Public Health Institute of Georgia · WHO consultant, health and migration

As Chair of the Public Health Institute of Georgia and a WHO consultant, I recognise that latent TB infection management remains a gap in many Georgian clinical settings despite our national TB programme's progress. This MSF guidance provides a pragmatic approach particularly relevant for our context: the permission to initiate preventive treatment without mandatory testing in high-risk groups (young child contacts and HIV-positive individuals) aligns with WHO recommendations and addresses our resource constraints. I would stress to Georgian clinicians that false negative TST results are common in HIV co-infected patients and malnourished children—populations we encounter regularly—making clinical judgment and active TB exclusion paramount. The main implementation challenge will be ensuring that primary care providers and TB dispensaries have clear protocols for active TB exclusion before initiating preventive therapy, as diagnostic capacity varies significantly between Tbilisi and regional centres.

ORCID 0000-0001-7609-4515 · Perspective written for the GMJ Guidelines Library, 21 Oct 2026

Applicability

Georgia and the South Caucasus

Georgia has an intermediate TB burden with ongoing national TB control programmes supported by the Global Fund and WHO. This MSF guidance on LTBI diagnosis is directly applicable to Georgian clinicians managing TB contacts and HIV co-infected patients. Given Georgia’s BCG vaccination programme and the prevalence of HIV co-infection in some populations, understanding the limitations of TST (false positives from BCG, false negatives in HIV) is essential. National programmes should consider whether IGRA technology is cost-effective and feasible given laboratory capacity constraints, or whether the simplified approach of treating high-risk groups (young child contacts, HIV-positive individuals) without mandatory testing is more pragmatic for resource-limited settings in the region.

Questions this guideline answers

Quick answers

When can I start LTBI treatment without performing a TST or IGRA?

Testing is not mandatory before initiating LTBI treatment in two groups: children under 5 years who are household contacts of a TB case, and children and adults with HIV infection. After excluding active TB, you can proceed directly to treatment.

Why might a TST be falsely positive in my patient?

Prior BCG vaccination commonly causes false positive TST results. Additionally, TST does not distinguish infection by M. tuberculosis from environmental mycobacteria, so exposure to non-tuberculous mycobacteria can also produce positive results.

Which patients are most likely to have false negative TST results?

False negative TST is common in patients with HIV infection and in malnourished children. In these populations, immunosuppression impairs the delayed-type hypersensitivity response that the TST relies upon.

What advantage do IGRAs have over TST?

IGRAs (QuantiFERON-TB Gold In-Tube and T-SPOT.TB test) do not cross-react with BCG vaccine or most environmental mycobacteria, making them more specific than TST. However, they require more complex laboratory infrastructure and trained technicians, and are not widely available.

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Same guideline

Active tuberculosis — MSF TuberculosisChapter 3: Diagnosis and follow-up investigations
Summary of clinical presentations of tuberculosis — MSF TuberculosisChapter 2: Clinical presentation
Clinical presentation of tuberculosis in HIV-infected persons — MSF TuberculosisChapter 2: Clinical presentation
Disseminated or miliary tuberculosis — MSF TuberculosisChapter 2: Clinical presentation
Extrapulmonary tuberculosis — MSF TuberculosisChapter 2: Clinical presentation
Pulmonary tuberculosis — MSF TuberculosisChapter 2: Clinical presentation

Latent tuberculosis infection — MSF Tuberculosis

What this guideline says

Key points

From the guideline