Maharashtra: Patients line up for S-gene tests at pvt labs; 45-64% samples positive

As genome sequencing takes time, several concerned Covid-19 positive patients are opting for SGTF test in private labs which costs Rs500.

Private laboratories believe that these tests are helping in an early diagnosis by differentiating the Delta and omicron cases. “This information helps the treating clinicians to decide on the use of monoclonal antibody injection cocktail for treatment of patients as it is a costly therapy generally reserved for patients infected with non-S gene Target failure (non-S gene knockout) cases of variants of concerns such as Delta or Delta plus of SARS-Cov-2,” said of Dr Nilesh Shah president at Metropolis Healthcare Ltd.

When The Indian Express contacted major private laboratories, it was found that the presence of Omicron at the community-level is gradually dominating that of Delta variants. Out of the total samples tested, Suburban Diagnostics found that 64% of them had S-gene knockout, indicating the presence of Omicron in patients. At Metropolis Healthcare Ltd, 45% of the samples reported the absence of S-gene.

Most of the private laboratories were conducting SGTF tests only on Covid-19 positive patients with international travel history in December 2021 when the third wave was initiated.

Later, it was extended to the general public to gauge community-level transmission.

“There was a high prevalence of SGTF positive cases in the patients we were testing, majority of them being international travellers in the beginning of last December and then seen in the general population who are non-travellers as well, indicating high spreadability of the virus,” said Dr Anupa Dixit, president, Lab Services, Suburban Diagnostics.

All private laboratories as per the state’s protocol inform the state.

The red-flagged samples are then prioritised for genome sequencing.

Dr Dixit said this has helped the government laboratories to narrow down on the samples for genome sequencing.

“The absence of S-gene is a red flag for Omicron ahead of genome sequencing. With the involvement of private laboratories, the overwhelmed laboratories can prioritise the samples for sequencing,” said Dr Shashank Joshi, member of the state Covid-19 task force.

Brihanmumbai Municipal Corporation (BMC) is also using SGTF kits for detection of suspected Omicron patients. “Not all samples of Covid-19 positive patients can be sent for genome sequencing. So, we have to select the samples cautiously and SGTF is one of the criteria,” said Suresh Kakani, additional commissioner, BMC.