Soon, though, molecular or genetic tests, which can detect TB in less than two hours, will replace sputum microscopy as the initial test. This follows the World Health Organisation’s (WHO) recommendation to use rapid molecular tests for early detection and higher diagnostic accuracy.
The change is already taking place across the world, including India where the small state of Goa recently became the first to go completely molecular with TB detection. (The microscopy test still has a role to play in subsequent treatment).
In Maharashtra, the change is still far away. While Mumbai—often described as the capital of difficult-to-treat, drug-resistant TB cases— had started using molecular test, an imported test called GeneXpert, as the first step to detect TB almost a decade back, a shortage of cartridges needed for the machines brought microscopy back in the picture a few months back (officials said the shortage is over).
“The BMC has 42 GeneXpert machines and seven Truenat ones,” said BMC executive health officer Dr Daksha Shah. Truenat is a made-in-India innovation, with over 6,000 machines deployed across the country in the past three years.
Maharashtra has 147 GeneXpert machines and 392 of Truenat. However, an estimate submitted by the state TB department to the union health ministry over a year ago said it needed at least 450 TrueNat machines to switch to complete molecular testing.
“Talks are in progress to acquire around 200 more Truenat machines that will help Maharashtra get closer to the goal of initial molecular testing for TB,” said a senior Maharashtra state official.
Last week, the state placed an order for 3.5 lakh Truenat test kits as the usual round of supplies from the Central TB Division are still awaited.
Roughly a year back, the state got 100 TrueNat machines as CSR from the Indian Oil Corporation Ltd.
“The goal of TB elimination requires a multi-stakeholder intervention. IOC is the first PSU that invested CSR funds towards India’s fight against TB. It donated 100 Truenat TB diagnostic machines to Maharashtra to ensure molecular testing at remote locations across the state,’’ said Shiva Sriram of Molbio, makers of Truenat.
The affordable option?
While WHO has asked for molecular tests to replace microscopy as the initial test, there is the all-important question as far as India is concerned: Which machine to use? GeneXpert is imported and its cartridges are expensive compared to Truenat machines. “Genexpert is definitely the more versatile machine as it gives a diagnosis within two hours of not only drug- sensitive TB but also the drug-resistant variant in one go. We need to run two tests of one hour each in Truenat machine,’’ said a senior doctor.
However, Truenat is much smaller in size—and cost— than GeneXpert. “It is portable. It doesn’t need electricity (runs on battery) or AC,” said state TB officer Dr Seema Golhait. GeneXpert machine has to be fixed and needs to be in a cold environment.
With most of the 1,000-odd GeneXpert machines in India around 7-10 years old and in need for an upgrade, the national TB programme has to take a call soon in this regard.