KOLKATA : The West Bengal Health department has written to the ICMR requesting it to change its guidelines on "immediate retest" of a person who has tested negative in antigen test for COVID-19, a senior official said on Tuesday.In this season of flu, there are people who are negative in antigen tests at several fever clinics but as per the Indian Council of Medical Research (ICMR) guidelines they should be sent for the RT-PCR test immediately, he said."We have a different opinion on this..., we think, a person who has tested negative in antigen tests, be sent for the Reverse transcription polymerase chain reaction (RT-PCR) test after a gap of at least three days and not immediately.