GOVT ALLOWS POOLED RT-PCR TEST FOR MIGRANT WORKERS
According to the guidelines to be followed for pooling samples, a cohort of 25 people will be identified, and throat/nasal swabs will be collected
NEW DELHI: Taking note of the health issues raised by the state governments that influx of migrant workers may add to the numbers of COVID19 positive cases as thermal screening is not enough to diagnose the presence of the virus in them, the Centre has decided to use one time RTPCR based pooled sampling for COVID-19 screening among migrant workers and returnees from abroad kept in quarantine facilities.
As per the guidelines issued by the Union Health Ministry for RT-PCR based pooled testing, the same investigation technique would also be used for monitoring in green zones districts which have reported no cases till now or in the last 21 days. The guidelines were issued on Thursday, a day prior to the start of booking of tickets for special passengers trains.
According to the experts, the decision in this regard has been taken after the state governments raised an alarm that the movement of migrants has created health challenges as most of the workers who have been quarantined are asymptomatic. “If any of them found positive, it will pose a major health challenge for respective states. The pooled-based sampling for RT-PCR test is the best way to diagnose the infection,” the experts stated.
“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 earmarked for quarantine and for surveillance purposes in green zones (districts with no case/no case reported in last 21 days),” the guidelines stated.
According to the guidelines to be followed for pooling of samples, a cohort of 25 people will be identified, and throat/ nasal swab will be collected as per the laid down protocol by trained laboratory personnel wearing appropriate protective gear such as apron, hand glove, face-shield/goggles and N-95 mask.
Proper labelling (name/age/ gender/specimen ID) needs to be done on specimen container, it said. The guidelines stated that 25 such samples of such cohort would be packed in triple layer packaging and will be transported to the identified laboratory under cold-chain as per ICMR guidelines.
“The outer container mentioning “be tested for SARSCOV-2” will also bear the details such as name, address, phone number of the sender. The samples will be aliquoted and thereafter pooled samples from 25 specimens would be tested in the laboratory by RTPCR method,” it said.
The report will be conveyed to the quarantine/concerned facility within 24 hours.
“If any of the pooled samples tests positive, individual samples would be tested from the aliquoted samples preserved in the laboratory,” the guidelines stated.
A pooled testing algorithm involves the PCR screening of a specimen pool comprising multiple individual patient specimens, followed by individual testing only if a pool screens positive.
According to the advisory issued by ICMR on April 13, all individual samples in a negative pool should be regarded as negative. The sample pooling for real-time RT-PCR screening for COVID-19 is only recommended in areas with a low prevalence of COVID-19 (initially using the proxy of low positivity of less than 2 per cent from the existing data.