WHO Expands TB Diagnostic Toolkit with Point-of-Care Tests, Tongue Swabs, and Sample Pooling
WHO introduces faster, more accessible TB testing strategies while CDC maintains a targeted, risk-based approach in the United States.
The World Health Organization (WHO) has issued new recommendations aimed at improving access to faster, more efficient tuberculosis (TB) diagnostics by introducing near point-of-care molecular testing, alternative sample collection methods, and pooled testing strategies, according to a news release.
For the first time, WHO is recommending a new class of near point-of-care nucleic acid amplification tests (NPOC-NAATs) that can be deployed in decentralized settings such as primary care clinics and community health centers. These systems are designed to deliver faster results at lower cost compared to traditional laboratory-based molecular platforms, potentially shifting more TB testing closer to the patient.
Clinical laboratory scientists should note that the WHO’s guidelines diverge noticeably from those of the Centers for Disease Control and Prevention (CDC).
The updated guidance also endorses tongue swabs as an alternative specimen type for TB detection, particularly for patients unable to produce sputum. In parallel, WHO recommends sputum pooling as a strategy to improve efficiency and reduce costs, allowing laboratories to increase throughput while conserving reagents in resource-constrained environments.
“These new WHO recommendations mark a major step forward in making TB testing faster and more accessible,” said Tereza Kasaeva, director of WHO’s Department for HIV, TB, Hepatitis & STIs. “WHO urges countries and partners to work together to roll out these guidelines to close persistent diagnostic gaps and ensure that everyone with TB can be diagnosed early and start life-saving treatment without delay.” (Photo credit: WHO)
The recommendations arrive as global diagnostic gaps persist despite international commitments to expand access to rapid molecular testing. Many patients still experience delays due to reliance on sputum samples, centralized laboratory infrastructure, and the high cost of testing platforms.
New WHO Recommendations Emphasize Access and Efficiency
WHO’s updated Module 3: Diagnosis guidelines, expected later this year, reflect a broader shift toward decentralization and scalability in TB diagnostics.
By enabling testing at peripheral healthcare levels, the new NPOC-NAAT systems could reduce turnaround times and expand access in underserved regions. Tongue swabs further simplify sample collection, while pooling strategies offer laboratories a practical way to stretch limited resources without sacrificing diagnostic reach.
Supporting materials, including an operational handbook and implementation toolkit, will guide laboratories and national TB programs through adoption, training, and workflow integration.
CDC Maintains Targeted Testing Approach in the US
In contrast to WHO’s global push for expanded access, the CDC continues to emphasize a targeted testing strategy for tuberculosis in the United States, focusing on high-risk individuals rather than universal screening.
TB case counts and rates have been increasing since 2021, the CDC noted in late 2025. The US saw a 7.9% increase in case count and a 6.9% increase in rate in 2024 as compared to a year earlier. In 2024, there were 10,388 TB cases in the US with a corresponding incidence rate of 3.1 per 100,000 population.
Two Types of TB Infection Tests
The CDC recognizes two primary methods to detect TB infection, though neither distinguishes between latent infection and active disease:
- TB blood tests: Preferred for most individuals, particularly those vaccinated with Bacille Calmette-Guérin (BCG). (BCG is primarily used to prevent severe childhood TB particularly in high-prevalence countries. BCG is generally not recommended in the US.)
- TB skin test: Still used in certain cases, especially for children under age five, and for baseline testing scenarios requiring a two-step approach.
Five Components of a Full Diagnostic Evaluation
If a patient tests positive or presents symptoms such as chronic cough, night sweats, or weight loss, the CDC recommends a comprehensive evaluation that includes:
- Medical history and risk assessment
- Physical examination
- Chest X-ray
- Bacteriologic testing using sputum samples (typically three), including:
- NAAT for rapid detection
- Sputum smear microscopy
- Culture
- Drug susceptibility testing to guide treatment decisions
Updated Guidance for Healthcare Personnel
Recent CDC guidance, developed with the National Tuberculosis Controllers Association, reflects a shift in screening practices for healthcare workers:
- Baseline TB testing is required upon hire
- Routine annual testing is no longer recommended for most healthcare workers
- Post-exposure testing is advised immediately and again eight to 10 weeks later if initial results are negative
For 2026, the CDC emphasizes several important nuances for clinicians and laboratories interpreting TB test results. Blood-based interferon-gamma release assays (IGRAs) are strongly preferred for individuals who have received the BCG vaccine, as they are less likely to produce false-positive results compared to skin tests. In addition, for individuals considered low risk for TB, a positive result should be confirmed with a second test—ideally using a different method—before treatment is initiated, helping to avoid unnecessary therapy and ensure diagnostic accuracy.
Implications for Clinical Laboratories
Together, WHO and CDC guidance illustrate a divergence in strategy shaped by global versus domestic needs. WHO’s recommendations prioritize expanded access, decentralization, and cost efficiency—particularly in high-burden or resource-limited settings—while CDC guidance reflects a more targeted, risk-based approach within a lower-incidence environment.
For clinical laboratories, the evolving landscape signals both opportunity and complexity: Adoption of decentralized molecular platforms, validation of alternative specimen types, and optimization of high-throughput workflows such as pooling may become increasingly important as TB diagnostic strategies continue to evolve.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
—Janette Wider
