Rapid antibody test for COVID-19 should be used only for surveillance and not diagnosis, the apex health research body said.
Detection of immunoglobulin G (IgG) antibodies for SARS-CoV-2 can be useful for conducting sero-surveys to understand the proportion of population exposed to the infection, including asymptomatic individuals, the Indian Council for Medical Research (ICMR) said.
IgG antibodies generally start appearing after two weeks of onset of infection once the individual has recovered and lasts for several months, it said.
Therefore, the IgG test is not useful for detecting of acute infection, the ICMR advisory on newer additional strategies for COVID-19 testing released on Tuesday said.
Besides, the ICMR also recommended deployment of rapid antigen detection test for COVID-19 in combination with the "gold standard" RT-PCR test in containment zones, central and state government medical colleges and government hospitals, private hospitals approved by the National Accreditation Board for Hospitals and Healthcare (NABH), and NABL accredited and ICMR approved private laboratories for COVID-19 testing.
Hospitals, laboratories and state governments intending to perform point-of-care (PoC) antigen test need to register with the ICMR to obtain the login credentials for data entry.
Data of testing needs to be entered on the ICMR portal on a real-time basis, the health research body said.
The ICMR portal has been modified to include a component on antigen testing.
"Labs/hospitals initiating testing through the rapid antigen point-of-care test need to ensure that all symptomatic negative patients should essentially be referred to a real-time RT-PCR test for COVID-19.
"This is particularly essential as the rapid antigen PoC test has a moderate sensitivity," the advisory said.
The entities using antigen PoC test are expected to tie up with the nearest RT-PCR COVID-19 testing laboratory to ensure that all symptomatic cases, who are negative by the rapid antigen test, get tested at the nearest facility, it said.
The ICMR encouraged manufacturers of all antigen-based tests to approach it for validation and inclusion of their test in the wider testing approach of the country.
The advisory said a positive test should be considered as a "true positive" whereas all symptomatic individuals testing negative through the rapid antigen test should be confirmed with a real-time RT- PCR test.
Since test, track and treat is the only way to prevent spread of the coronavirus infection and save lives, it is imperative that testing should be made widely available to all symptomatic individuals and contact tracing mechanisms strengthened, the ICMR said.
"ICMR advises all concerned state governments, public and private Institutions to take required steps to scale up testing for COVID-19 by deploying combination of various tests as advised," the advisory stated. PLB ANB ANB