From UPSC perspective, the following things are important :
Prelims level : Gene sequencing, RTPCR
Mains level : COVID diagnosis
Omisure — India’s first home-grown testing kit has recently received approval from the Drugs Controller General of India.
- Omisure is an omicron detecting RT-PCR kit developed by the Mumbai-based Tata Medical and Diagnostics Ltd (TATA MD) in partnership with the Indian Council of Medical Research (ICMR).
- It can differentiate the omicron strain of the novel coronavirus from the delta, alpha and the other variants in under four hours.
- It can diagnose this variant in a single step
How does it work?
- This new kit can identify the Omicron variant by targeting two regions of the S or the spike gene.
- This gene codes for the spike protein, which helps the novel coronavirus enter and infect human cells.
- The S, the Enveloped (E), and Nucleocapsid (N) genes are some of the targets of conventional RT-PCR tests.
- When it detects these genes, a patient sample is labelled positive. As omicron bears heavy mutations in the S gene, the RT-PCR can sometimes miss it.
- The absence of S gene likely indicates omicron’s presence.
- This is called S gene dropout or S gene target failure — and is one of the targets of Omisure.
How does Omisure compare with gene sequencing?
- Gene sequencing reads the order of nucleotides, which are the building blocks of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
- Despite being considered the gold standard, sequencing has a few limitations.
- It is slow, expensive and complicated. It is a multi-step process.
- It begins with extracting the virus’ RNA from patient samples, converting it into DNA, amplifying or multiplying it through RT-PCR before finally sending it for gene sequencing.
- This entire process can take as many as three days.