ICMR also informed in what circumstances the newly approved test is supposed to be undertaken.
Coronavirus in India: The Indian Council of Medical Research (ICMR) on Monday gave its approval to another kind of test – the rapid antigen detection test. The nodal health agency fighting against COVID-19 in India, the ICMR on Sunday issued an advisory on the use of these rapid antigen tests, also detailing how the test differs from the RT-PCR test, which is being used to determine whether a person is COVID-19 positive or not. ICMR also informed in what circumstances the newly approved test is supposed to be undertaken.
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Here’s all you need to know about the rapid antigen detection test.
Rapid antigen detection test explained
According to the ICMR, the rapid antigen detection test is conducted on the nasal swab sample and it checks for the presence of antigens, or foreign substances which trigger an immune response, in people. The test can be used as a rapid point of care test to determine quickly whether a person has or has had the infection, in a setting outside of the conventional laboratory.
The ICMR said that these tests would help the government in properly implementing the testing, tracking and treating strategy and also allay the fears of healthcare workers.
Since there are no reliable antigen tests, ICMR said that an independent two-site evaluation was undertaken of the only available or standalone antigen test called the Standard Q COVID-19 Ag detection kit. It has been developed by South Korean company SD Biosensor for qualitative detection of antigens specific to SARS-CoV-2, the coronavirus which caused COVID-19, the ICMR said. SD Biosensor also has its manufacturing unit in Manesar, Gurgaon.
How is rapid antigen test different from RT-PCR?
RT-PCR is the test most widely being conducted to test whether someone has the COVID-19 infection or not. Both RT-PCR and rapid antigen detection test check whether the virus is present in the patient or not, rather than checking for the presence of antibodies to the SARS-CoV-2. However, the RT-PCR, which also takes nasal samples, gives results in a minimum period of two to five hours, and it requires to be conducted in a specialised laboratory, with specific equipment, biosafety and biosecurity. ICMR said that the test result can be interpreted within 15 minutes, usually, and a maximum time of 30 minutes has been stipulated.
The test has been approved after being evaluated by the ICMR as well as the All India Institute of Medical Sciences (AIIMS), Delhi. ICMR has recommended that only Standard Q COVID-19 Ag detection assay be used for conducting this test.
When can Rapid antigen detection test be used?
The ICMR has enlisted when the test can be used. The test would have to be conducted onsite under strict medical supervision .
- Containment zones or hotspots: It should be conducted in containment zones or hotspots in cases of all symptomatic Influenza-Like Illness (ILI) and among asymptomatic people who are direct and high-risk contacts having co-morbidities, like lung disease, heart disease, kidney disease, diabetes, liver disease, blood disorders and neurological disorders. In such cases, the test should be conducted once between five and 10 days of coming in contact with a confirmed case.
- Healthcare settings: The test should be conducted among all symptomatic ILI patients presenting in a healthcare setting and who are COVID-19 suspects. Apart from this, asymptomatic patients in the high-risk zone and seeking hospitalisation or having been hospitalised should also undergo this test. The high-risk zone patients are those who are undergoing chemotherapy, have been diagnosed with a malignant disease, have undergone transplants, who are immunosuppressed, including those who are HIV positive, or are over the age of 65 and have co-morbidities. Moreover, asymptomatic patients who are undergoing aerosol-generating surgical or non-surgical interventions, including elective or emergency procedures like neurosurgery, dental procedures or ENT surgery and non-surgical interventions like bronchoscopy, dialysis and upper GI endoscopy can also be tested using the antigen test.
ICMR also stated that people who are suspected to be suffering from the infection and have tested negative in the antigen test must be tested sequentially for RT-PCR to ensure that there is no infection. On the other hand, a person who tests positive for the infection using this test should be considered to have the infection and it need not be followed up with an RT-PCR.