Context

• Tuberculosis (TB) remains a major public health challenge, particularly in India. Recent advancements endorsed by the World Health Organisation (WHO) have significantly transformed TB diagnostics.
• The emergence of near point-of-care tests, molecular diagnostics, and AI-enabled tools has improved detection, efficiency, and accessibility.
• However, persistent gaps in implementation, access, and research must be addressed to achieve 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, mobile vans equipped with these technologies have expanded community-based screening.
• AI enables rapid identification of suspicious lesions, allowing opportunistic screening in both public and private healthcare settings.
• This reduces diagnostic delays and improves early detection; however, effective implementation requires on-the-spot sputum collection, proper referral systems, and strong microplanning to target vulnerable populations, including those in urban slums and tribal areas.

Evolution of Molecular Testing in India

• India’s diagnostic approach has shifted from sputum smear microscopy to advanced nucleic acid amplification tests (NAAT).
• The introduction of CBNAAT and Truenat has enabled rapid detection of TB and drug resistance.
• This shift has strengthened the overall diagnostic accuracy and reduced reliance on less sensitive methods.
• Despite progress, uneven access to molecular testing remains a concern. Strengthening sample collection, transport systems, and laboratory capacity is essential, especially for the elderly, disabled, and populations in remote areas.
• Reducing turnaround time is critical to ensure timely treatment, particularly for drug-resistant TB cases.
• The expansion of decentralised testing through NPOC-NAAT allows testing at primary healthcare levels.
• Additionally, non-sputum samples such as tongue swabs improve 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 required, combining AI-enabled imaging and molecular tests.
• Diagnostic network optimisation helps determine the best combination of tools for different settings, ensuring accessibility, affordability, and efficiency.
• Implementation must be guided by evidence-based research. Institutions like the Indian Council of Medical Research play a crucial 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

• First, there is a need for cost-effective biomarkers to identify individuals at high risk of disease progression, improving TB preventive therapy (TPT) uptake.
• Second, asymptomatic TB requires broader screening beyond symptoms, using CXR access and non-invasive diagnostics such as saliva-based tests.
• Third, paediatric TB diagnosis remains difficult due to low bacterial load and inability to produce sputum.
  • Alternative approaches like stool-based testing require further research.
• Fourth, 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 need further validation.
• Finally, community engagement is essential. Addressing screening hesitancy and improving awareness through community-led programmes can increase uptake of diagnostics and preventive therapy.

Conclusion

• Strengthening TB diagnostics offers one of the highest returns in public health. Early diagnosis improves treatment outcomes, reduces transmission, and minimises long-term complications.
• It also lowers out-of-pocket expenditure for affected 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, and fostering community participation.
• A robust, evidence-based diagnostic strategy can accelerate progress toward eliminating TB and improving overall public health.