Context: Recently, the Indian Council of Medical Research (ICMR) has advised the feasibility of using pooled samples for molecular testing of Covid-19 citing the rise of cases in India.The advisory also stated that it is important to increase the number of tests being done in laboratories in India.
Key Points

• Stating that the number of COVID-19 cases in India is rising, the Indian Council of Medical Research (ICMR) is now advising the feasibility of using pooled samples for molecular testing of patient samples. 
• The council has said that it is critical to increase the numbers of tests conducted by laboratories. 
• The advisory is aimed at increasing capacity of the laboratories to screen increased numbers of samples using molecular testing for COVID-19 for the purpose of surveillance.

About Pooled Testing

• A pooled testing algorithm involves the PCR screening of a specimen pool comprising multiple individual patient specimens, followed by individual testing (pool de-convolution) only if a pool screens positive. 
• As all individual samples in a negative pool are regarded as negative, it results in substantial cost savings when a large proportion of pools tests negative.
• This method is effective in two ways. First, it increases the capacity of testing and second, it saves a lot of resources — time, cost and manpower.

As per ICMR Recommendation

• 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 is strongly discouraged to pool more than five samples, except in research mode.
• This method can be used in areas where the prevalence of COVID-19 is low, which means a positivity rate of less than two percent. 
• In areas with a positivity rate between two to five percent, sample pooling of PCR screening may be considered in a community survey of surveillance among asymptomatic individuals. Sample from such individuals should be directly tested without pooling.

Need of Pool testing

• This will reduce the total test kits used to examine patients and treat them.
• It is also expected to trim the work at the laboratories testing these samples.
• International researchers suggest that pooling test samples is cost effective, especially for the countries with limited resources.
• It can be used to prevent community spread of the disease.

About Indian Council of Medical Research (ICMR) 

• The is the apex body in India for the formulation, coordination and promotion of biomedical research and it is one of the oldest and largest medical research bodies in the world.
• The ICMR is funded by the Government of India through the Department of Health Research, Ministry of Health and Family Welfare.
• The governing body of the council is presided over by the Union Health Minister.