A research laboratory funded by the Department of Science and Technology has developed a rapid diagnostic test that can potentially speed up the testing of a batch of suspected COVID-19 samples by 15 times and cut costs by two-thirds.
The Chitra GeneLAMP-N, made by scientists at the Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), Thiruvananthapuram, has already been licensed to Agappe Diagnostics Ltd., an Ernakulam-based company. If approvals come through, about 20,000 kits could be made by the month-end, said Asha Kishore, director, SCTIMST.
Union Health Minister Harsh Vardhan tweeted: “Sree Chitra Tirunal Institute for Medical Sciences & Tech, Trivandrum, an Institute of National Importance, of the @IndiaDST, has developed a diagnostic test kit that can confirm #COVID19 in 2 hours at a low cost.”
Though qualified by the National Institute of Virology’s sister organisation — NIV Alappuzha — as fit to be offered as a diagnostic, the kit awaits formal approval by the Indian Council for Medical Research and its manufacturers, and a licence from the Central Drugs Standard Control Organisation.
Rapid-Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) tests are considered the gold standard for detecting the virus. It involves extracting RNA from a swab, collected from the throat or nose, converting it into DNA, magnifying the quantity of DNA and using chemical probes to bind target genes that distinguish SARS-CoV2 from other viruses. While it takes two hours to extract RNA from a given batch of samples, the analysis can take two-and-a-half hours to detect the presence (or absence) of virus in a given batch.
‘Analyse in 10 minutes’
By employing its in-house technology called reverse transcriptase loop-mediated amplification of viral nucleic acid (RT-LAMP), it zooms in on regions of the virus’ nucleocaspid (N) gene and can analyse a batch in 10 minutes.
Most RT-PCR kits focus on two different genes, the E (envelope) gene and the RdRP (RNA dependent RNA polymerase) gene. The WHO recommends a E and RdRP test, while the U.S.’s Centres for Disease Control requires an N Gene test. “The N-Gene test is a confirmatory test and widely employed in Germany and China among other countries. However, the design of it is complicated and can be expensive. However, we’ve managed to develop it satisfactorily while keeping costs low,” said Dr. Kishore. The CDC protocol says three regions of the N gene must be analysed but the Chitra-model tests two to confirm the identity of the virus.
Anoop Thekkuveettil, a senior scientist of the biomedical technology wing of the institute, was able to develop the kit in 3 weeks, she said.
Tests conducted at the NIV Alappuzha showed that it detected 100% of all reference COVID samples and successfully detected 100% of non-COVID samples. While some kits approved by the ICMR and currently in use for diagnosing the infection have a similar 100% profile, some don’t. In the spirit of accelerating testing, the scale of the pandemic has moved regulatory agencies around the world to ease standards and facilitate the availability of more kits.
A total of 30 samples can be tested in a single batch and the unit consists of an RNA extraction machine, which too is locally developed. Probes, a critical aspect of PCR testing and frequently imported, for this test can be procured from several places in India. “Everything can be made and developed in India, except for some sensors in the analysis machine,” Dr. Kishore emphasised.
