False negatives are high in rapid testing, a potentially dangerous situation, says a doctor
There has been talk about conducting rapid coronavirus tests across the state. States are planning to import rapid test kits from China to undertake screening populations for the virus infection.
But experts like Dr Raghava Gundavarapu doubt the efficacy of the rapid tests in detecting the depth of the virus penetration into the community. Unless the tests are conducted on a mass scale and by trained virologists, a fool-proof containment of COVID-19 is not possible, says the reputed and public-spirited doctor from Ongole, Andhra Pradesh. He warns of reactivation of virus as in South Korea, if India fully relies on rapid tests.
Stating that the increase in positive cases in Andhra Pradesh is not exponential and not alarming, Dr Raghava Gundavarapu said the state has to rope in virology experts to conduct tests for reliable data.
“Still not much testing is being carried out in the state. There are no clinical profiles and demographic profiles of the people who were tested positive. The data clearly points toward community transmission, though the Central government is denying,” he said.
Stressing that the tests need to be conducted by virology experts, not the locally available lab technicians, Dr Raghava said and added that in Ongole, officials are planning tests by technicians, not even by those with an MD in microbiology.
Talking to The Lede Dr Raghava said large scale testing alone could give a correct picture of the width and breadth the virus penetrated into the community. Positive cases are like the tip of an iceberg and to know the actual depth of an iceberg the state needs to do more tests by the more qualified personnel, Dr Raghava remarked.
“We need to get more scholars from various virology PhD programs into action. They should be doing the tests. They are the eyes in the present scenario. There are institutes like IISc Bangalore around, the government should get them out of the lockdown,” he said.
Referring to other countries that embarked on mass-scale testing, Dr Raghava said in addition to the qualified personnel to conduct tests, these countries have regular surveillance mechanisms.
“They collect random nasal and throat samples and test for the virus presence even among the common cold patients. This is made a continuous process as they have trained personnel,” he said.
Elaborating on the inadequacy of rapid tests, he said they are only for screening purposes, especially for large scale screening, at a lesser cost. “However, they are less reliable. More false-negative or false-positive results can occur in the rapid test. False-negative means, even if the person is infected with the virus, the test comes negative. If we let this false-negative person into the community, he can spread the virus to more people. As opposed to this, if false positive reports are higher, then we are going to create panic in the society,” he warned.
Dr Raghava favoured the immunoglobulin tests. “If IgG (Immunoglobulin G) is positive then it indicates presence of infection and if IgM is positive, it indicates that the person is immune to the virus. if more people in the community have IgM that means most of the people in the community are immune to the virus and we can breathe easy,” he said.
The UK government, he said, is switching to IgM tests for all those who are coming forward for voluntary testing.
Citing the South Korean example where the reactivation of coronavirus cases is occurring, Dr Raghava said there is a lesson for India in the Korean experience.
“The reactivation of coronavirus is the result of rapid tests. Initially, a few cases test positive. The patient would be treated and post-treatment test shows (a false) negative. He would be sent home. Again on follow up he would test positive.”
According to the officials, Andhra Pradesh is conducting 2100 tests per day now. The state has plans to step up the tests to 4000 tests in a week or so, which, according to Dr Raghava, is not adequate to gauge the real picture of the virus penetration.