An analysis of negative rapid antigen tests (RAT) that came positive when retested withRT-PCRhas proved that RAT missed up to 33.7% cases. The finding assumes significance since RAT accounts for more than 60% of the dailyCovid-19 testsin the state, being preferred for its ease of use and shorter turnaround time.
The study was based on field data from tests conducted at Icmr-National Institute of Research in Reproductive Health (NIRRH) between July 7 and August 7, 2020.
The institute studied its own Database of 412 antigen negative reports that were retested with RT-PCR (reverse transcription polymerase chain reaction), the gold standard test to detect coronavirus. It found that the repeat RT-PCR could pick up 139 positives (33.7%) that were missed by antigen.
The state is carrying out an Average of 2.4 lakh tests of which around 1.3 lakh are antigen tests and the rest are RT-PCR tests.