After the Indian Council of Medical Research's (ICMR) advisory, several states in India have either started pool testing or are in the process to start the lost cost testing to increase the speed of coronavirus tests. Given the increasing coronavirus hotspots in the country and limited test kits, the ICMR said that it was crucial to increase the number of tests being done to detect coronavirus infection. However, the ICMR said that the pooling of samples is "not recommended" in "areas or population with positivity rates of >5 percent for COVID-19.
"Preferable number of samples to be pooled is five, though more than two samples can be pooled, but considering higher possibility of missing positive samples with low viral load, it strongly discouraged to pool more than 5 samples, except in research mode,' the ICMR advisory said.
There is an acute shortage of coronavirus testing kits in India and Andaman and Nicobar Union Territory is the first in India to start pool testing the samples of suspected coronavirus patients in order to reduce the number of kits used. Uttar Pradesh government has notified that they will also start pooling samples.
What is pool testing and how it's done?
It is a process that involves the screening of a pooled sample from five individuals. For this, health officials will collect swab samples of five people in a single test tube and if the pool tests positive, all the five patients will be tested individually.
"All individual samples in a negative pool to be regarded as negative. De-convoluted testing is recommended if any of the pool is positive. Pooling of more than 5 samples is not recommended to avoid the effect of dilution leading to false negatives," the ICMR said.
Video: How pool testing would work
India may begin pooled testing of up to 5 #COVID19 samples to significantly ramp up testing with limited resources, per Apr 13 advisory from @ICMRDELHI. Increasing testing is critical to prevent the spread of the virus. Here's how that would work: pic.twitter.com/CaEK8v1bjD— IndiaSpend (@IndiaSpend) April 15, 2020
India has only tested nearly 2.31 lakh samples due to the shortage of testing kits. Given the country's 1.3 billion population, this is a minimal amount and this could mean that the actual number of positive cases in the country could be way more than what's being told since a lot of people have not yet been tested.
There are more than 3 lakh people in quarantine in India waiting for their tests to be done. Pool testing could speed up the procedure, thus, giving a clear picture of coronavirus cases in the country. As of now, India has more than 10,000 coronavirus positive cases.