The Evolving Tuberculosis

Tuberculosis (TB) remains a major public health challenge, particularly in India, which bears a significant proportion of the global TB burden. Recent technological advancements, endorsed by the World Health Organization (WHO), have transformed TB diagnostics, improving detection, efficiency, and accessibility. Despite these innovations, persistent gaps in implementation, access, and research must be addressed to achieve TB elimination goals.

Technological Advancements and Their Impact

The introduction of near point-of-care (NPOC) tests, tongue swabs, and sputum pooling has made TB testing faster and more scalable.

A major breakthrough is the use of portable chest X-rays (CXR) combined with artificial intelligence (AI) for screening. Under the National TB Elimination Programme (NTEP), mobile vans equipped with these technologies have expanded community-based screening, enabling rapid identification of suspicious lesions.

This approach facilitates opportunistic screening in both public and private healthcare settings, reducing diagnostic delays and improving early detection. Effective implementation, however, depends on on-the-spot sputum collection, proper referral systems, and robust microplanning, especially for urban slums and tribal areas.

Evolution of Molecular Testing in India

India’s diagnostic approach has evolved from sputum smear microscopy to advanced nucleic acid amplification tests (NAAT).

The introduction of CBNAAT and Truenat allows rapid detection of TB and drug resistance, improving overall diagnostic accuracy and reducing reliance on less sensitive methods.

Despite progress, uneven access to molecular testing remains a concern. Strengthening sample collection, transport systems, and laboratory capacity is critical, particularly for the elderly, disabled, and remote populations. Reducing turnaround time is essential for timely treatment, especially in drug-resistant TB cases.

The expansion of decentralized NPOC-NAAT testing at primary healthcare levels, along with non-sputum samples like tongue swabs, improves access for individuals who cannot produce sputum, including children.

The Need for a Comprehensive Diagnostic Strategy

No single diagnostic tool can address all challenges. A comprehensive diagnostic toolbox is necessary, combining AI-enabled imaging and molecular tests.

Diagnostic network optimization helps determine the best combination of tools for different settings, ensuring accessibility, affordability, and efficiency.

Implementation must be guided by evidence-based research, with institutions like the Indian Council of Medical Research (ICMR) playing a key role in evaluation, validation, and health technology assessment. Streamlined procurement systems ensure that only effective and safe tools are scaled up across public and private sectors.

Persistent Gaps and Research Priorities

Several gaps remain in TB diagnostics:

1. Cost-effective biomarkers are needed to identify high-risk individuals and improve TB preventive therapy (TPT) uptake.

2. Asymptomatic TB requires broader screening beyond symptom-based detection, using CXR access and non-invasive diagnostics like saliva-based tests.

3. Paediatric TB is difficult to diagnose due to low bacterial load and inability to produce sputum; alternative approaches like stool-based testing need further research.

4. Extra-pulmonary TB (EP-TB) diagnosis is often delayed, expensive, and inaccessible, leading to misdiagnosis and poor outcomes. Emerging solutions like AI-enabled ultrasound combined with molecular tools show promise but require further validation.

5. Community engagement is critical. Addressing screening hesitancy and improving awareness through community-led programmes can increase uptake of diagnostics and preventive therapy.

Conclusion

Strengthening TB diagnostics provides one of the highest returns in public health. Early diagnosis improves treatment outcomes, reduces transmission, minimizes long-term complications, and lowers out-of-pocket expenditure for families.

India’s expanding diagnostic ecosystem, driven by innovation, research, and policy support, provides a strong foundation for TB elimination. Achieving this goal requires:

• Ensuring equitable access

• Improving implementation efficiency

• Advancing research

• Fostering community participation

A robust, evidence-based diagnostic strategy can accelerate progress toward eliminating TB and improving overall public health.