The Omicron variant of the SARS-CoV-2 virus has been confirmed in India and in at least 30 other countries by the World Health Organization (WHO).
What is the S-gene drop out?
While the variant can only be reliably confirmed with genome sequencing, the WHO has also recommended that certain commonly used COVID-19 detection tests, with ‘S-gene dropout’ capabilities, can be used to quickly screen for an Omicron infection.
Tests usually look for three target genes related to parts of the virus: S (spike), N2 (nucleocapsid or inner area) and E (envelope or outer shell).
The S-gene refers to the gene that codes for the spike protein, or the most distinctive part of the coronavirus.
The SARS-CoV-2, like many other coronaviruses, has key protein-regions that define its structure: The envelope protein (E), thenucleocapsid protein(N), the membrane protein (M) and the spike protein (S).
To accurately identify the virus, diagnostic tests are made that can identify characteristic genes that make these proteins.