TrueNat is a chip-based, portable RT-PCR machine, originally developed as a portable diagnostic tool for tuberculosis by Goa-based startup Molbio Diagnostics.
TrueNat machine can detect an enzyme (called RdRp) found in the RNA of the coronavirus SARS-CoV-2.
On 19 May, the ICMR revised its testing guidelines to allow the use of the TrueNAT system for screening and confirmation of Covid-19.
*The chip-based test works by detecting the SARS-CoV-2 E-gene*, which helps build the envelope that holds the components of the coronavirus together, and the gene for the RNA-dependent RNA polymerase, an enzyme that enables the virus to replicate.
Unlike traditional RT-PCR tests, the sample preparation in TrueNAT tests is automated, and the results are available within half an hour
The test uses nose or throat swab samples, which are collected from patients and dipped in a solution that inactivates the virus.
A few drops of the solution are then placed on a cartridge. On inserting this cartridge into a machine, a pre-programmed reaction is initiated, which extracts the nucleic acids or the genetic material from the samples.
This has to be followed by an RT-PCR. The purified nucleic acid is added into a micro-tube containing freeze-dried RT-PCR reagents, and the solution is allowed to stand for about a minute.
This solution is then applied to a microchip and the test is inserted into another machine, where the reverse transcription and PCR take place.
The advantage of this test is that it is quick and portable. This allows teams to set up mobile testing centres or kiosks in containment zones, instead of having to transport samples to labs.
TrueNAT is an indigenously developed, portable version of *CB-NAAT or Cartridge Based Nucleic Acid Amplification Test*, also known as the Genexpert test. Both these tests were initially developed for testing tuberculosis.
While both versions are cheaper and quicker than RT-PCR tests, TrueNAT is battery operated and portable, while CB-NAAT machines need an uninterrupted power supply and air conditioning, and hence cannot be deployed in containment zones.