India's Century-Old TB Diagnosis Method Gets a Modern Overhaul
For more than one hundred years, the global standard for tuberculosis detection relied on a simple yet flawed process: examining a patient's sputum sample under a microscope with a trained technician's eye. This method, known as smear microscopy, was notoriously imprecise, detecting only about half of all TB cases and missing one out of every two infections. This diagnostic gap significantly hampered treatment efforts worldwide.
India's Persistent TB Burden and the Diagnostic Revolution
India continues to shoulder a disproportionate share of the global tuberculosis crisis, accounting for nearly one-fourth of the world's total TB burden. According to the World Health Organisation's Global TB Report 2025, India reported 187 cases per 100,000 population in 2024. Despite decades of implementing the DOTS strategy (Directly Observed Treatment, Short Course) through India's National Tuberculosis Elimination Programme, persistent diagnostic shortcomings slowed progress toward elimination goals.
The landscape began transforming dramatically over the past decade with the introduction of molecular diagnostics, which brought unprecedented accuracy to TB testing. Two platforms have driven this diagnostic revolution: GeneXpert, developed by US-based Cepheid, and Truenat, created by India's own Molbio Diagnostics. Both represent automated, rapid molecular tests capable of detecting Mycobacterium tuberculosis and identifying resistance to rifampicin, a crucial first-line TB drug, within one to two hours. Both technologies have received approval from WHO and India's tuberculosis elimination programme as frontline diagnostic tools.
Accessibility Challenges and Point-of-Care Solutions
Under India's national programme, these molecular tests cost between 600 and 800 rupees, covering both TB detection and identification of multidrug-resistant (MDR) TB strains. Sriram Natarajan, founder and CEO of Molbio Diagnostics, explains the strategic difference between the two platforms: "Launched seven years ago, Truenat was specifically designed as a point-of-care solution for primary health centers. It successfully brought molecular testing closer to patients, unlike GeneXpert which, over ten years, remained largely confined to district hospitals."
Today, Truenat technology operates at approximately 11,000 of India's roughly 24,000 DOTS centers. Despite this expansion, only about 45% of TB centers currently utilize molecular diagnostics as their primary testing method. Sarang Deo, a member of WHO's Strategic and Technical Advisory Group for Tuberculosis, identifies ongoing challenges: "Significant hurdles remain in reducing costs and ensuring consistent availability at the district level." He adds another critical limitation: many patients cannot produce sputum samples, which remain the primary specimen required for most current tests.
Next-Generation Diagnostics: Tongue Swabs and AI Screening
This sputum barrier is precisely what the latest diagnostic platforms from India's Molbio and China's Pluslife Biotech aim to overcome. These innovative systems, currently under evaluation, utilize tongue swabs instead of sputum while maintaining compatibility with existing testing protocols. WHO has recently recommended such near-point-of-care molecular tests using tongue-swab samples for pilot introduction, noting they could prove cheaper and easier to deploy widely.
Madhukar Pai, Chair of the Global and Public Health department at Canada's McGill University, emphasizes the global significance: "Rapid molecular testing has remained inaccessible for many countries due to high costs and expensive imported technologies. With affordable near-point-of-care tests now being manufactured in the global south, it's exciting to see Indian innovations that work with tongue swabs. India now has the opportunity to scale these up to replace outdated smear microscopy."
Hyderabad-based Huwel has partnered with Pluslife to advance this technology, while Molbio awaits necessary clearances. "This advancement will help scale up testing for people who cannot produce sputum," Natarajan confirms.
Reaching the Unreached: AI-Powered Screening
The sputum challenge represents only half the diagnostic problem. Millions of TB patients, particularly asymptomatic carriers, never visit testing centers at all. For this population, ultra-portable digital X-ray machines enhanced with artificial intelligence serve as a critical first screening filter. Shibu Vijayan, Chief Medical Officer at health technology startup Qure.ai, which developed such a machine, reports: "The government has adopted AI as a strategic tool for chest X-ray interpretation, conducting large-scale screenings in Delhi, Telangana, Maharashtra, and Mizoram." Individuals who screen positive through this AI-powered system are then referred for molecular confirmation.
India's ambitious tuberculosis elimination goal, originally targeted for 2025, remains an ongoing endeavor. The technological constraints that once limited progress have largely been overcome. The central question now focuses on implementation speed: how rapidly can India deploy these advanced diagnostic tools across its vast healthcare landscape to finally turn the tide against this ancient disease?
