New TB Tests Offer Faster Diagnosis with Tongue Swabs and Sputum Pooling

The World Health Organization (WHO) is recommending new strategies to accelerate the detection of tuberculosis (TB), including near-point-of-care (NPOC) molecular tests, the use of tongue swabs for sample collection, and a sputum pooling strategy to improve testing efficiency. These advancements aim to expand access to TB diagnosis and treatment, particularly for drug-resistant forms of the disease.

The Challenge of TB Diagnosis

Tuberculosis remains a significant global health threat. Rapid and accurate diagnosis is crucial for effective treatment and preventing further spread. Traditional TB diagnosis relies heavily on sputum samples, which can be difficult to obtain from some patients, especially children and individuals with limited access to healthcare facilities.

New WHO Recommendations

Recent evidence has prompted the WHO to update its guidelines on TB diagnosis. The key recommendations, published shortly, include:

Near-Point-of-Care (NPOC) Molecular Tests

The WHO now recommends a new class of NPOC nucleic acid amplification tests (NPOC-NAATs) for the initial detection of TB, without immediately testing for rifampicin resistance, at peripheral levels of the health system. This allows for quicker results closer to the patient, reducing turnaround time for diagnosis.

Tongue Swabs for Easier Sample Collection

Effortless-to-collect tongue swab samples are now recommended as a viable alternative to sputum samples. Research has demonstrated the ability of oral and tongue swabs to detect Mycobacterium tuberculosis (Mtb) in adults with pulmonary TB [1]. While further research is needed to optimize methods, current data suggest that tongue swabs, and those collecting increased biomass, may have increased sensitivity [2].

Sputum Pooling for Increased Efficiency

A cost-saving sputum pooling strategy is recommended to increase testing efficiency for both TB and rifampicin-resistant TB. This involves combining multiple sputum samples into a single test, reducing the cost per test and allowing for more individuals to be screened.

Diagnostic Accuracy of Alternative Methods

Rapid, accurate, nonsputum tests are vital to address gaps in TB detection. Molecular testing on saliva and oral swabs is being evaluated for its diagnostic performance [3]. While high accuracy is achievable with oral swabs and molecular testing, ongoing research is crucial to define optimal methods for their use.

Implications for Global TB Control

These new recommendations represent a significant step forward in the global effort to complete TB. By simplifying sample collection, accelerating diagnosis, and improving testing efficiency, these strategies have the potential to dramatically increase TB detection rates and improve patient outcomes. The WHO Department leads the global effort to end the epidemics of HIV, tuberculosis (TB), hepatitis, and sexually transmitted infections (STIs) [4].