New mutant seems to be undetectable by RTPCR test. I believe there are double and triple mutant varieties and due to change in structure, RTPCR tests unable to detect. New varieties seem to cause new symptoms: Dr Chandra, consultant physician, Helvetia Medical Centre, Delhi
According to ANI, Chandra further added, "We're seeing patients with diarrhoea, abdominal pain, rashes, conjunctivitis, confusion state, brain fog, bluish discolouration of fingers and toes, bleeding through nose and throat apart from usual symptoms -- sore throat, body ache, fever, loss of smell and taste."