New Delhi: For over a century, tuberculosis was diagnosed using a sputum sample, a microscope and a trained eye. But smear microscopy was a blunt tool, with barely 50% sensitivity, missing one in two cases. India still accounts for nearly a fourth of the world’s TB burden – 187 cases per lakh population in 2024, according to the World Health Organisation’s Global TB Report 2025. And despite decades of the DOTS strategy – directly observed treatment, short course – under India’s National Tuberculosis Elimination Programme, gaps in diagnosis continued to hold back progress.
That began to change over the past decade, as molecular diagnostics brought a major jump in accuracy and became the new standard. Two platforms drove that shift: GeneXpert, made by US firm Cepheid, and Truenat, developed by India’s Molbio Diagnostics. Both are rapid, automated molecular tests that can detect Mycobacterium tuberculosis as well as resistance to rifampicin, a key TB drug, in one to two hours. Both have also been approved by WHO and India’s tuberculosis elimination programme as frontline tests.
Under the national programme, the tests cost between Rs 600 and Rs 800, with both covering TB detection as well as identification of multidrug-resistant, or MDR, TB. “Launched seven years ago, Truenat was designed as a point-of-care solution for primary health centres. It brought molecular testing closer to the patient, unlike GeneXpert which over 10 years remained largely confined to district hospitals,” says Sriram Natarajan, founder and CEO of Molbio Diagnostics.
Today, Truenat is used at 11,000 of the country’s roughly 24,000 DOTS centres. Even so, only about 45% of TB centres currently use molecular diagnostics as the upfront test. “Challenges remain in cutting costs and ensuring district-level availability,” says Sarang Deo, a member of WHO’s Strategic and Technical Advisory Group for Tuberculosis. Another limitation, he adds, is that some patients are unable to produce sputum, which remains the primary sample required.
That is what the latest platforms from India’s Molbio and China’s Pluslife Biotech are trying to address. These systems, now being evaluated, use tongue swabs instead of sputum while retaining compatibility. WHO has recently recommended such near-point-of-care molecular tests, using tongue-swab samples, for pilot introduction, saying they could be cheaper and easier to deploy. Wider adoption, however, is still some way off.
Madhukar Pai, Chair, Global and Public Health department at McGill University in Canada, says, “Rapid molecular testing has been out of reach for many countries owing to high costs and expensive imported technologies. With affordable NPOC tests now being manufactured in the global south, it is exciting to see Indian innovations that can be used with tongue swabs. India can now scale them up to replace the old smear microscopy.” Hyderabad-based Huwel has partnered with Pluslife for this, while Molbio is awaiting clearance. “This will help scale up testing on people who can’t produce sputum,” says Natarajan.
But the sputum barrier is only half the problem. Millions with TB, especially ones who are carriers, never come to a centre at all. For them, an ultra-portable digital x-ray can be the critical first filter, armed with artificial intelligence. Shibu Vijayan, CMO at health tech startup Qure.ai, which has made the machine, says, “Govt has adopted AI as a strategy for chest x-ray interpretation, with large-scale screenings in Delhi, Telangana, Maharashtra, and Mizoram.” Those who screen positive are referred for molecular confirmation.
India’s TB elimination goal – originally set for 2025 – remains a work in progress. Tools are no longer the constraint. The question is simply how fast India can move.
