April 23, 2021 Experts believe that 98-99% assays can pick up all the strains of virus RT-PCR continues to be the gold standard for Covid-19 diagnosis with 98-99 per cent of assays used in the country picking up the virus, Priya Abraham, Director of the Pune-based National Institute of Virology (NIV), an Indian Council of Medical Research constituent lab, said on Friday. If this diagnostic test was throwing up false negatives, as reported in a section of the media, that could be either because of inappropriate sampling or compromised integrity of reagents, she said. In the extremely stressful situation in a clinical setting, sampling may be inappropriate, individuals may be appearing late for sampling, or improper transportation of the kits can lead to loss of the integrity of enzymes used for the RT-PCR test, she said. Abraham and a few other experts were participating in a webinar on SARS-Cov2 mutants, organised by the National Biopharma Mission.