What is Pool Testing for COVID-19 and why ICMR advised it?
On Monday, the Indian Council of Medical Research (ICMR) issued an advisory to began Pool Testing as the number of positive COVID-19 cases in India is increasing rapidly. Currently, India has 9,756 active cases and 377 deceased. In view of this, it is important to increase the numbers of tests conducted by laboratories.
What is Pool Testing?
As per the advisory issued by ICMR, Pool Testing works on Polymerase Chain Reaction (RT-PCR) screening algorithm. In this, multiple samples (up to 5) are tested in a single test. In case, the result of a pool resulted positive, then each sample is tested individually. However, the RT-PCR test is only prescribed to be used in the areas with a low rate of infection- the rate of positive cases less than 2%.
What is the objective of Pool Testing?
The main aim of Pool Testing is to increase the testing capacities of labs. This technique also saves time, reduces the cost and the manpower.
Why only 5 samples are advised in Pool Testing?
As per the advisory issued by ICMR, pooling of more than 5 samples is not recommended to avoid the effect of dilution as it leads to false negatives. The advisory further stated that as few as two samples can be pooled and the preferrable number to pool the samples is five.
Pool Testing is effective in which areas?
As per the advisory issued by the ICMR, apart from the areas having low rates of infection, areas having positivity rates between 2-5 can carry out Pool Testing technique.
ICMR also stated that Pool Testing can be used in community survey/ among the individuals without any symptoms. However, Pool Testing is prohibited in the case of individuals who have had direct contact with positive cases.
This method is effective in the areas where the infection rate is low as it increases the capacity of testing and reduces time, cost and manpower. Pool Testing for more than 5 samples can only be done in research mode, as per ICMR.
The government is taking all the necessary measures to contain the spread of the highly contagious virus. The ICMR approved pooling of samples to diagnose results as a measure of mass testing in communities and to increase the capacity of the laboratories to screen increased numbers of samples using molecular testing for COVID-19 for the purpose of surveillance.