Explanation:

• Recently, the Indian Council of Medical Research (ICMR) issued an advisory for using pooled samples for testing of COVID-19 in order to increase the number of tests conducted by laboratories across the country.
• In a pooled testing algorithm, samples of multiple individuals are put together in a tube and screened through the PCR test.
• In case the pooled test turns out to be positive, individual samples are tested, which is referred to as pool de-convolution. If there’s no positive result, all individual samples in the pool are regarded as negative.
• However, ICMR has said pooling of sample is not recommended in areas or population with positivity rates of over five per cent. Hence statement 3rd is incorrect.
• Hence, this method can be used in areas where the prevalence of COVID-19 is low, which implies a positivity rate of less than two percent.