Q Why is it in News ?
- Recently, the Indian Council of Medical Research (ICMR) approved India’s first self-use Rapid Antigen Test (RAT) for Covid-19 named as CoviSelf.
- It is developed by MyLab Discovery Solutions, a Pune-based molecular company.
- ICMR is the apex body in India for the formulation, coordination and promotion of biomedical research, and is one of the oldest medical research bodies in the world.
Q What is Coviself ?
- It uses a RAT and gives results within 15 minutes. This test is synced with a mobile app, CoviSelf, which will help directly feed the positive case’s report on the ICMR portal.
- ICMR has advised this test only for those who have symptoms or are high-risk contacts of positive patients and need to conduct a test at home.
- This test is not advised for general screening in public places of hawkers, show owners, or commuters.
Q How does it works ?
- It is a test on swabbed nasal samples that detects antigens (foreign substances that induce an immune response in the body) that are found on or within the SARS-CoV-2 virus.
- It is a point-of-care test, performed outside the conventional laboratory setting, and is used to quickly obtain a diagnostic result.
- Like RT-PCR (Reverse Transcription Polymerase Chain Reaction), the RAT too seeks to detect the virus rather than the antibodies produced by the body.
- While the mechanism is different, the most significant difference between the two is time.
- In an RT-PCR test, RNA (Ribonucleic acid) is extracted from the swab collected from the patient. It is then converted into DNA (Deoxyribonucleic acid), which is then amplified.
- RT-PCR test takes a minimum of 2-5 hours whereas the maximum duration for interpreting a positive or negative test in RAT is 30 minutes.
Q What are benefits of Self Testing ?
- Cost Effective:
- Swab collection in this case is fairly simple and quick, and reduces overall testing expenditure and the stress of booking appointments in labs.
- It is cheaper than RT-PCR and a RAT in the laboratory.
- Reduced Risk of Transmission:
- A person testing himself at home rather than visiting a hospital or lab, or calling a technician at home, reduces the risk of transmission to others.
- Reliable self-collection and self-testing will reduce population movement, reduce Covid-19 exposure risk.
- Reduced Burden:
- Self-testing will reduce the burden on laboratories that are currently working 24 hours up to full capacity with manpower that is already saturated.
- Mass Surveillance:
- Cheap rapid tests can help in accomplishing the aim of mass surveillance even if their sensitivity to capture accurate results are inferior to other tests.
Q What are some concerns related to it ?
- The reliability of results remains a major concern. The likelihood of the sample not being collected correctly, or the swab stick getting contaminated, is high.
- False Sense of Security:
- RAT comes with a high chance of false negatives. If a Covid-infected person is asymptomatic and tests negative, the test may give a false sense of security.
- Challenge to Response Measures:
- Shifting the responsibility of reporting test results from health professionals and laboratories to individuals could lead to underreporting, and make response measures such as contract tracing and quarantine of contacts even more challenging.
Q What can be way forward ?
- Self-tests can be effective if the patient follows isolation norms, feeds correct data and is able to interpret the results accurately.
- However while a RAT serves as a quick mass surveillance tool, over-dependence on it for testing is not advisable. It can supplement, not form, the bulk of testing.