COURTESY HT MAY 15
Health ministry issues pool testing rules
rhythma.kaul@htlive.com
New Delhi : Migrant workers and international passengers in institutional quarantine, people under isolation in hotels, and random samples of those living in green zone districts will be pool tested for prevalence of the coronavirus disease (Covid-19), according to new Union health ministry guidelines released on Thursday.
A pool of 25 samples from the target population will be tested using the reverse transcription polymerase chain reaction (RT-PCR) method to detect the presence of Sars-Cov-2, the virus that causes Covid-19.
In pool testing, throat or nasal swabs from two to five people are mixed and tested as a single unit. All individual samples in a negative pool are deemed as having tested negative; if a pooled sample tests positive, each person in the pool is tested individually to find out who is infected.
“Guideline for RT-PCR based pooled sampling for migrants/returnees from abroad/green zones… A decision has been taken to use one time RT-PCR based pooled sampling for surveillance purposes for migrant workers in institutional quarantine facilities, international passengers in institutional quarantine facilities/hotels ear-marked for quarantine and for surveillance purposes in green zones…” reads a health ministry directive.
The green zone districts from where samples will be collected are those from where no case has been reported to date, or districts which had reported cases earlier but have been clean for the past 21 days or more.
“It is one time only testing to check whether there is infection prevalent in a particular group or not. If a pool sample returns positive, then all the samples will be individually tested for the presence of virus,” said a health ministry official, who did not wish to be identified.
The responsibility of conducting the test will lie on respective state governments.As per the protocol, a cohort of 25 people will be identified, and throat or nasal swabs will be collected by trained laboratory personnel using appropriate protective gear