E-Paper
Covid-19: Haryana ramps up pool testing
Pool sampling accounts of over 27% of total testing done in last 7 days
Haryana has gone big on sample pooling, testing 2,348 samples in the last seven days, thus increasing the lab capacity to screen samples using molecular testing for Covid-19.
The pool-tested samples account for more than 27% of the total samples tested in the last seven days.
The virology lab of Post Graduate Institute of Medical Sciences (PGIMS) in Rohtak started pool sampling on April 14 with 229 samples. Since then, it has consistently tested pooled samples in the range of 220 to 494.
According to Indian Council for Medical Research (ICMR), a pooled testing algorithm involves real-time reverse transcription polymerase chain reaction test (rRT-PCR) screening of a specimen pool comprising multiple individual patient specimens.
If a pool sample tested negative, it means no individual testing and substantial cost savings. If only a pool sample is tested positive, then all the individual samples are to be tested separately.
Nodal officer for Covid-19 at PGIMS, Dr Dhruva Chaudhary, said with pool sampling and arrival of new testing machines, they would be able to scale up the testing up to 5,000 samples per day. The chief secretary has given us a target of testing 10,000 samples per day by enhancing our testing capability, he added.
Professor Paramjeet Singh Gill, in-charge of virology lab at PGIMS, said the pool testing can be done only where incidence of infection is less than 2% in populations. “We are pooling three samples for testing, though the ICMR has recommended pooling five samples. But since we got good results by pooling three samples, we are continuing with it,” Prof Gill said.
He said out of 2,348 pooled samples tested by the virology laboratory at PGIMS, only 17 have turned out to be positive for coronavirus.
Senior health officials said the pool sampling will significantly enhance the capability to test more as is evident by the big surge in total sampling (individual as well as pool) from 6,163 on April 14 to 14,562 on April 21.
As per health officials, pool sampling is recommended in the areas with low prevalence of infection.
“In areas where 2 to 5% population is infected, sample pooling can be considered only in community survey or surveillance among asymptomatic individuals, strictly excluding pooling samples of individuals having known contact with confirmed cases and health workers in direct contact with care of coronavirus positive patients. Samples from such individuals should be directly tested without pooling,” said an official.
He said that pooling of sample was not recommended in areas or population with positivity rates of over 5% for Covid-19.
