Explainer: What is CoviSelf, when to self-test, and how it fares vs other Covid-19 tests

The photo is for representational purpose only

On Wednesday, May 20, the Indian Council of Medical Research (ICMR) approved a Covid-19 self-testing kit for home use, a first for India. In simple terms, symptomatic individuals and those around them can use the kit as guided by ICMR to test their nasal swabs for Covid-19, without having to call healthcare professionals.

This DIY kit uses the rapid antigen test process. It is should be noted that rapid antigen tests reportedly come with a high probability of showing false negatives. Last year, the ICMR in an advisory had stated, "There are no reliable antigen detection tests available worldwide, which could be used as rapid point of care tests for quick detection of Covid-19 positive patients."

Here is a breakdown of everything you need to know about this self-testing kit and other existing Covid-19 tests.

What is the ICMR-approved self-testing kit?

The kit is called CoviSelf, and had been developed by MyLab Discovery Solutions, a Pune-based molecular biology company. The firm had also been the first in the country to produce RT-PCR kits last year. Until now, in India, Covid-19 tests had only been conducted by health professionals. CoviSelf uses a rapid antigen process, in which a nasal swab sample can be tested for the virus at home and the result is obtained within 15 minutes.

When should the test be taken?

The ICMR has advised against indiscriminate Covid-19 home testing using Rapid Antigen Tests (RATs), saying it should be used only on symptomatic individuals and on the immediate contacts of laboratory-confirmed positive cases.

How does it work?

The kit comprises a pre-filled extraction tube, sterile nasal swab, instruction manual, a testing card, and biohazard bag. The individual's details have to be entered on a CoviSelf app, which will reportedly store data on a secure server connected with the ICMR portal, where all test reports are available to government.
After sanitising their hands and surfaces, the individual will have to insert the swab, without touching its head, 2-4 cm into their nose, and swirl it well inside each nostril to collect the specimen. The swab will have to be dipped inside an extraction tube to mix with the liquid inside. The tube will have to be tightly shut, and two drops from the extraction tube's outlet be put onto the testing card. After you are done, seal the tube and swab in the biohazard bag and dispose it off as biomedical waste.

The result is said to be obtained within 15 minutes. If two lines appear on the testing card, as specified, it means a person is positive. If a single line appears, the person is negative. If it takes more than 20 minutes to show, then the test is invalid.

What happens after the results?

As stated by ICMR in an advisory, "All individuals who test positive through the RAT kit may be considered as true positives and no repeat testing is required". It continued, "All symptomatic individuals who test negative by RAT should get themselves immediately tested by RT-PCR. This is especially important as the RATs are likely to miss few positive cases presenting with a low viral load." The advisory also stated, "All RAT negative symptomatic individuals may be treated as suspect Covid-19 cases and are advised to follow the ICMR/Ministry of Health home isolation protocol while awaiting the RT-PCR test result."

What is the price of the kit and where can one buy it?

The cost of the kit is Rs 250 and it will be available by end of next week in pharmacies and online platforms.

How reliable is self-testing?

In March 2020, European Centre for Disease Prevention and Control released a document on self-tests for Covid-19. It had stated that, "The reliability of the test result depends on a few factors: the ability of the person taking the sample and performing the test to follow instructions, the viral load at the time of the sampling, and the disease prevalence in the population when the test is taken."

The report said that it can support detecting the disease but it cannot be a substitute for traditional testing. "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."

What are the different types of Covid-19 tests that have been in use so far?

RT-PCR (reverse transcription-polymerase chain reaction): One of the most common tests being conducted in India is the RT-PCR. This test requires collecting nasal and throat swabs by healthcare professionals and is used to directly detect the presence of the virus rather than antibodies.

Rapid antibody test: Antibody tests require a blood sample to determine whether the human body has antibodies for coronavirus. It is not 100 per cent reliable. Last year, in April, the ICMR had issued a notice which stated that this test is "a supplementary tool to assess the prevalence of the diseases within a specified area/perimeter." It also stated that it cannot "replace real time PCR based molecular test."

Rapid antigen tests: Similar to the RT-PCR test. Nasal swabs are collected and tested for antigens. Antigens refers to any substance in the body that generates an immune response.

(With inputs from PTI, ANI)

Disclaimer: This article is not a medical advice. Please contact your doctor about medical procedures.

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