S-gene Target Failure (SGTF) Test

Subject – Science and Tech

Context – Union health ministry said the Omicron variant will be identified only through genome sequencing and through S-gene target failure,

Concept –

The World Health Organization has said the S gene is not present in the Omicron variant. This is the result of the multiple mutations that the variant has undergone and is a marker to identify the variant.
RT-PCR tests in India, as of now, only focus on the E, N and Rd Rp genes and the S test was not required.
S gene drop detecting kits can be used for early detection of Omicron. This way, Omicron can be detected even before genome sequencing. This is known as a proxy test.
SGTF was defined as non-detection of the S-gene target among samples that tested positive (cycle threshold <37) for both the N-gene and ORF1ab gene targets.