A day after the Indian Council of Medical Research (ICMR) issued an advisory for pool testing for COVID-19 in areas where rate of positive cases were less than five per cent, officials in Maharashtra said with a positivity rate of 5.7 per cent in the state, they will not be able to do pool testing anywhere.
Pool testing can help cut cost and time required to test each sample. In countries like Germany, 15 samples are all tested in one bunch as one specimen by Polymerase Chain Reaction (PCR) technique. If it tests negative, that means all 15 samples are negative; if it tests positive then each sample has to be individually re-tested to check which ones came positive. Pool testing can significantly increase testing capacity in laboratories. Maharashtra currently has a capacity of 2,000 tests in government labs and 3,000 in private labs per day. With pool testing, capacity can rise by four to five times.
The ICMR in its advisory on Monday proposed to states to do pool testing only in areas where incidence of COVID-19 is low. It recommends pool testing in areas where less than 2 per cent of samples test positive. For areas where positivity is between 2 and 5 per cent, pool testing can only be done for community surveillance and of asymptomatic people from general population. It is not meant for close contacts, health workers, or those who come under high risk.
For states having positivity above 5 per cent, pool testing has not been recommended. Maharashtra has a positivity of 5.7 per cent — 2,684 of 46,588 lab samples have tested positive. “We want to do pool testing but ICMR guidelines currently do not allow it. Maharashtra has approached ICMR to frame policy for testing,” a state official said.
The ICMR has also advised to not test more than five samples in one pool. Maharashtra officials said they wish to test more than five swabs in one pool.